Accounting Policies [Abstract] Accounting Policies [Abstract] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract] Outstanding principal and carrying value of acquired loans recorded at fair value Accrued Investment Income Receivable Accrued interest receivable Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Defined Benefit Plans [Member] Accumulated net unrealized investment gain loss all other. Accumulated Net Unrealized Investment Gain Loss All Other [Member] Investment Securities All Other [Member] Accumulated net unrealized investment gain loss with OTTI. Accumulated Net Unrealized Investment Gain Loss With OTTI [Member] Investment Securities With OTTI [Member] Accumulated Other Adjustment [Member] Accumulated Other Adjustment [Member] Accumulated Other Adjustment [Member] AOCI Including Portion Attributable to Noncontrolling Interest, before Tax Ending balance, before tax Beginning balance, before tax The tax effect of the accumulated change in equity from transactions and other events and circumstances from non-owner sources. Excludes the tax effect of Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes the tax effect of foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Accumulated Other Comprehensive Income Loss Income Tax Ending balance, tax Beginning balance, tax Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss), Net of Tax Ending balance Beginning balance Accumulated other comprehensive income (loss), net Accumulated Other Comprehensive Income (Loss) [Table] Schedule of Accumulated Other Comprehensive Income (Loss) [Table] AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss), Net [Member] Accumulated other. Accumulated Other [Member] Other [Member] Acquired Loans At Discount [Member] Acquired Financing Receivable At Discount [Member] Accruing Loans Acquired at Discount [Member] The amount included in assets of acquired loans that were recorded at fair value at the acquisition date. Acquired Loans At Fair Value Carrying Amount Carrying amount The outstanding principal balance of acquired loans that were recorded at fair value at the acquisition date. Acquired Loans At Fair Value Outstanding Principal Outstanding principal balance Additional Collateral, Aggregate Fair Value Fair value of additional collateral to be posted for derivative financial instruments Additional Paid in Capital Additional paid-in capital Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities Affordable Housing Tax Credits and Other Tax Benefits, Amount Federal tax credits and other federal tax benefits recognized Allocated. Allocated [Member] Allocated [Member] Other Segments [Member] All Other [Member] Allowance for Loan and Lease Losses Write-offs, Net Net charge-offs Amendment Flag Amendment Flag Amortization Method Qualified Affordable Housing Project Investments, Amortization Investments amortized to income tax expense Amortization of Intangible Assets Amortization of core deposit and other intangible assets Amortization of Mortgage Servicing Rights (MSRs) Amortization of capitalized servicing rights Amortized cost and estimated fair value of debt securities by contractual maturity. Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity [Table Text Block] Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity Amortized cost and estimated fair value of investment securities. Amortized Cost And Estimated Fair Value Of Investment Securities [Table Text Block] Amortized Cost and Estimated Fair Value of Investment Securities Amortized Cost and Fair Value Debt Securities [Abstract] Amortized Cost and Fair Value Debt Securities [Abstract] Amortized Cost and Fair Value Debt Securities [Abstract] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive securities excluded from computation of earnings per share Asset Impairment Charges Asset write-downs Assets Total assets Assets [Abstract] Assets Assets, Fair Value Disclosure Total assets Assumed in acquisition. Assumed In Acquisition [Member] Assumed In Acquisition [Member] Automobile Loan [Member] Automobile [Member] Available-for-sale Debt Securities, Amortized Cost Basis Total Available-for-sale Securities Investment securities available for sale, estimated fair value Available for sale (cost: $11,578,829 at June 30, 2016; $12,138,636 at December 31, 2015) Investment securities Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Investment securities available for sale, gross unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Investment securities available for sale, gross unrealized losses Available-for-sale Securities, Amortized Cost Basis Investment securities, available for sale, amortized cost Investment securities available for sale, amortized cost Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Estimated fair value, Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Estimated fair value, 12 months or more Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Due after five years through ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Due after five years through ten years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Due after one year through five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Due after one year through five years Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Due after ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Due after ten years Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract] Debt securities available for sale: Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] Debt securities available for sale: Available-for-sale Securities, Debt Maturities, Single Maturity Date Total available for sale (fair value) Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Total available for sale (amortized cost) Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Due in one year or less Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Due in one year or less Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis Mortgage-backed securities available for sale Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value Mortgage-backed securities available for sale Available-for-sale Securities, Debt Securities Total Average Assets Average Asset Average Assets Average asset difference amount. Average Asset Difference Amount Average assets Basis of Accounting, Policy [Policy Text Block] Basis of Accounting Bayview Financial [Member] Bayview Financial [Member] Bayview Financial [Member] Bayview Lending Group And Bayview Financial [Member] Bayview Lending Group And Bayview Financial [Member] Bayview Lending Group and Bayview Financial [Member] Bayview Lending Group [Member] Bayview Lending Group [Member] Bayview Lending Group [Member] Brokerage Commissions Revenue Brokerage services income Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Common stock issued Shares issued upon acquisition Business Acquisition [Line Items] Business Acquisition [Line Items] Business Acquisition, Pro Forma Information [Abstract] Business Acquisition, Pro Forma Information [Abstract] Business Acquisition, Pro Forma Information [Table Text Block] Pro Forma Information Business Acquisition, Pro Forma Net Income (Loss) Net income pro forma Business Acquisition, Pro Forma Revenue Total revenues pro forma Business Banking Segment. Business Banking [Member] Business Banking [Member] Business Combination, Consideration Transferred Total consideration Total consideration Total purchase consideration Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Common stock issued (25,953,950 shares) Business Combination Disclosure [Text Block] Acquisitions Business Combination Increase Decrease To Reflect Liabilities Acquired At Fair Value [Abstract] Business Combination Increase Decrease To Reflect Liabilities Acquired At Fair Value [Abstract] Business Combination Increase Decrease To Reflect Liabilities Acquired At Fair Value [Abstract] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Total identifiable assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Identifiable assets: Carrying amount of short-term and long-term debt acquired at the acquisition date, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Borrowings Borrowings Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Cash and due from banks Amount of assets, excluding financial assets and goodwill, lacking physical substance with a finite life acquired at the acquisition date. Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Core Deposit And Other Intangibles Core deposit intangible Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities Investment securities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Loans The aggregate of all interest-bearing and noninterest-bearing deposit liabilities acquired at the acquisition date. Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Deposits Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Core deposit intangible assets Amount of interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet, acquired at the acquisition date. Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Interest Bearing Deposits At Banks Interest-bearing deposits at banks Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Total liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Liabilities: Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Other liabilities Business Combinations [Abstract] Business Combinations [Abstract] Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed Merger-related expenses Total merger-related expenses Reported Value Measurement [Member] Carrying Amount [Member] Carrying value of loans in a residential mortgage loan securitization trust which the reporting entity has determined that it is the primary beneficiary. Carrying Value Of Loans In Securitization Trusts Carrying value of loans in the Securitization trusts Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Cash and Due from Banks Cash and due from banks Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental schedule of noncash investing and financing activities Certain loans acquired in transfer accounted for as debt securities accretable yield accretion. Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Accretion [Table Text Block] Summary of Changes in Accretable Yield for Acquired Loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Balance at end of period Balance at beginning of period The amount of interest from acquired loans included in earnings. Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Interest Income Interest income This item represents other changes in the accretable yield due to changes in expected cash flows including changes in interest rates and prepayment assumptions. Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Interest Other Increase Decrease Other Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Summary of changes in Accretable Yield for acquired loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Reclassifications from nonaccretable balance, net Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value Contractual principal and interest payments Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Purchased impaired Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves. Change In Fair Value Of Nonrecurring Fair Value Measured Loans For Charge Offs And Impairment Reserves Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves The tabular disclosure of changes in allowance for credit losses. Changes In Allowance For Credit Losses [Table Text Block] Changes in Allowance for Credit Losses The tabular disclosure of changes in level 3 assets and liabilities measured at estimated fair value on recurring basis. Changes In Level Three Assets And Liabilities Measured At Estimated Fair Value On Recurring Basis [Table Text Block] Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis Class of Stock [Domain] Class of Stock [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Class of Warrant or Right, Exercise Price of Warrants or Rights Exercise price of each class of warrants or rights outstanding Class Of Warrant Or Right Expiration Year Class Of Warrant Or Right Expiration Year Warrants, year of expiration Class of Warrant or Right, Number of Securities Called by Warrants or Rights Exercise of warrants into shares of common stock Class of Warrant or Right, Outstanding Warrant to purchase common stock Warrants and rights outstanding Clearinghouse Credit Facilities [Member] Clearinghouse Credit Facilities [Member] Clearinghouse Credit Facilities [Member] Collateral Already Posted, Aggregate Fair Value Fair value of collateral already posted for derivative financial instruments Collateralized Debt Obligations [Member] Collateralized Debt Obligations [Member] Collectively evaluated for impairment. Collectively Evaluated For Impairment [Member] Collectively Evaluated for Impairment [Member] Combination of concession types. Combination Of Concession Types [Member] Combination of Concession Types [Member] Combined Outstanding Principal Amount Of Mortgage Backed Securities Issued By Qualified Special Purpose Trusts Held By Unrelated Parties Combined Outstanding Principal Amount Of Mortgage Backed Securities Issued By Qualified Special Purpose Trusts Held By Unrelated Parties Combined outstanding principal amount of mortgage-backed securities issued by qualified special purpose trust held by unrelated parties Commercial Banking Segment. Commercial Banking [Member] Commercial Banking [Member] Commercial financial leasing. Commercial Financial Leasing [Member] Commercial, Financial, Leasing, etc. [Member] Commercial real estate excluding residential builder and developer and other construction. Commercial Real Estate Excluding Residential Builder And Developer And Other Construction [Member] Commercial [Member] Commercial Real Estate [Member] Commercial Real Estate [Member] Commercial Real Estate Portfolio Segment [Member] Commercial Real Estate [Member] Commercial Real Estate Segment. Commercial Real Estate Segment [Member] Commercial Real Estate [Member] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Text Block] Commitments and contingencies Commitments regarding Commercial letters of credit. Commitments Regarding Commercial Letters Of Credit Commercial letters of credit Commitments regarding Financial guarantees and indemnification contracts. Commitments Regarding Financial Guarantees And Indemnification Contracts Financial guarantees and indemnification contracts The tabular disclosure of commitments. Commitments [Table Text Block] Company's Significant Commitments Commitments to Extend Credit. Commitments To Extend Credit [Abstract] Commitments to extend credit Commitments to extend credit for Commercial and other. Commitments To Extend Credit For Commercial And Other Commercial and other Commitments to extend credit for Commercial real estate loans to be sold. Commitments To Extend Credit For Commercial Real Estate Loans To Be Sold Commercial real estate loans to be sold Commitments to extend credit for Home equity lines of credit. Commitments To Extend Credit For Home Equity Lines Of Credit Home equity lines of credit Commitments to extend credit for other commercial real estate. Commitments To Extend Credit For Other Commercial Real Estate Other commercial real estate Commitments to extend credit for Other residential real estate. Commitments To Extend Credit For Other Residential Real Estate Other residential real estate Commitments to extend credit for Residential real estate loans to be sold. Commitments To Extend Credit For Residential Real Estate Loans To Be Sold Residential real estate loans to be sold Commitments to originate real estate loans for sale. Commitments To Originate Real Estate Loans For Sale Commitments to originate real estate loans for sale Commitments to sell real estate loans. Commitments To Sell Real Estate Loans [Member] Commitments to Sell Real Estate Loans [Member] Commitments To Sell Real Estate Loans Net Commitments To Sell Real Estate Loans Net Commitments to sell real estate loans Commitments To Sell Real Estate Loans Notional Amount. Commitments To Sell Real Estate Loans Notional Amount Commitments to sell real estate loans The weighted average number of common shares outstanding (including common stock issuable) and unvested stock-based compensation awards. Common Shares Outstanding Including Common Stock Issuable And Unvested Stock Based Compensation Awards Common and unvested stock-based compensation awards Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards Common Stock, Dividends, Per Share, Cash Paid Cash dividends per common share Common stock per share dividend amount The obligation to issue shares of Company common stock in connection with deferred compensation plans. Common Stock Issuable Common stock issuable, 33,546 shares at June 30, 2016; 36,644 shares at December 31, 2015 Common stock issuable. Common Stock Issuable [Member] Common Stock Issuable [Member] Number of shares of common stock issuable in connection with deferred compensation plans. Common Stock Issuable Share Common stock issuable, shares Common Stock [Member] Common Stock [Member] Common Stock, Par or Stated Value Per Share Common stock, par value Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Value, Issued Common stock, $.50 par, 250,000,000 shares authorized, 159,957,393 shares issued at June 30, 2016; 159,563,512 shares issued at December 31, 2015 Compensation and Retirement Disclosure [Abstract] Compensation and Retirement Disclosure [Abstract] The tabular disclosure of components of other comprehensive income loss. Components Of Other Comprehensive Income Loss [Table Text Block] Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total comprehensive income Total comprehensive income Comprehensive Income (Loss) Note [Text Block] Comprehensive income Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] The noncash increase of investment securities held for sale resulting from securitization of residential mortgage loans. Consolidation Securitized Trusts Increase Investment Securities Held For Sale Securitization of residential mortgage loans allocated to Available-for-sale investment securities Consumer Loan [Member] Consumer Loans [Member] Consumer Portfolio Segment [Member] Consumer [Member] Contractual Interest Rate Reduction [Member] Interest Rate Reduction [Member] Cost Method Investments Cost method investment securities Credit Derivatives [Line Items] Credit Derivatives [Line Items] Credit risk derivative. Credit Risk Derivative [Member] Credit Risk Derivative [Member] Criticized accrual. Criticized Accrual [Member] Criticized Accrual [Member] Criticized nonaccrual. Criticized Nonaccrual [Member] Criticized Nonaccrual [Member] Current Fiscal Year End Date Current Fiscal Year End Date Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Text Block] Borrowings Debt Instrument, Basis Spread on Variable Rate Discount margin over LIBOR Debt Instrument, Maturity Date Range, End Debt Maturity, End Year Debt Instrument, Maturity Date Range, Start Debt Maturity, Start Year Debt Instruments [Abstract] Debt Instruments [Abstract] Decrease In Net Income Decrease In Net Income Decrease in net income Decrease In Revenues Decrease In Revenues Decrease in revenues Deferred Income Tax Expense (Benefit) Provision for deferred income taxes Defined Benefit Plan, Amortization of Gains (Losses) Amortization of net actuarial loss Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of prior service credit Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Expected Return on Plan Assets Expected return on plan assets Defined Benefit Plan, Interest Cost Interest cost on projected benefit obligation Defined Benefit Plan, Net Periodic Benefit Cost Net periodic benefit cost Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Defined Benefit Plan, Service Cost Service cost