AA Credit Rating AA Credit Rating Accounts, Notes, Loans and Financing Receivable [Line Items] Amortization and Accretion of Securities and Unearned Income Amortization and Accretion of Securities and Unearned Income Accumulated Defined Benefit Plans Adjustment, Before Reclassification Adjustments Accumulated Defined Benefit Plans Adjustment, Before Reclassification Adjustments Accumulated Defined Benefit Plans Adjustment Accumulated Defined Benefit Plans Adjustment, Reclassification Adjustments Accumulated Defined Benefit Plans Adjustment, Reclassification Adjustments Accumulated Net Gain (Loss) From Designated Or Qualifying Cash Flow Hedges, Before Reclassification Adjustments Accumulated Net Gain (Loss) From Designated Or Qualifying Cash Flow Hedges, Before Reclassification Adjustments Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges Accumulated Net Gain (Loss) From Designated Or Qualifying Cash Flow Hedges, Reclassification Adjustments Accumulated Net Gain (Loss) From Designated Or Qualifying Cash Flow Hedges, Reclassification Adjustments Accumulated Net Unrealized Investment Gain (Loss) Accumulated Net Unrealized Investment Gain (Loss), Reclassification Adjustments Accumulated Net Unrealized Investment Gain (Loss), Reclassification Adjustments The tax effect for noncredit-related losses recognized in other comprehensive income for debt securities held for which an other-than-temporary-impairment loss has been recognized in the period presented or previously. Tax Effect Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Loss Ending Balance (Net of Tax) Beginning Balance (Net of Tax) Noncredit-related losses recognized in other comprehensive income for debt securities held for which an other-than-temporary-impairment loss has been recognized in the period presented or previously. Noncredit-related (Losses) Recognized in OCI Noncredit-related (Losses) Recognized in OCI Amount Recorded in OCI Amount Recorded in OCI Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss), Unrealized Gains (Losses) on Available for sale Securities, Net of Tax Net unrealized gain and loss related to securities, net of tax Accumulated Other Comprehensive Income (Loss) Accumulated Translation Adjustment Additional Paid in Capital, Common Stock Additional Paid-In Capital Additional Paid-in Capital Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities: Stock Options and Awards - Tax Benefits This represents Affordable Housing Investment. Affordable Housing Investments Share-Based Compensation Expense Allowance for Credit Losses and Recorded Investment in Loans and Leases by Segment Allowance for Credit Losses Net Charge-Offs Net Charge-Offs Effect of Foreign Exchange Rates Allowance for Loan and Lease Losses, Provision for Loss, Net Provision for Credit Losses Charge-Offs Charge-Offs Alt-A Residential Mortgage Backed Securities Alt-A Amendment Flag Amortization of Computer Software Amortization of Computer Software Amortization of Intangibles Amortization of Stock Based Plan. Stock Options and Awards - Amortization Common stock equivalents not included in the computation of diluted earnings per share because their inclusion would have been antidilutive Asset And Liability Management Asset And Liability Management Total Assets Total Assets Assets [Abstract] Assets Fair Value Asset Total Assets at Fair Value Auction Rate Available for Sale Fair Value Amortized Cost Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis Due After Five Years Through Ten Years Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value Due After Five Years Through Ten Years Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis Due After One Year Through Five Years Available-for-sale Securities, Debt Maturities, after One Through Five Years, 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 Total Available for Sale - Amortized Cost Available for Sale - Fair Value Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis Due in One Year or Less Available-for-sale Securities, Debt Maturities, within One Year, Fair Value Due in One Year or Less Available-for-sale Securities, Debt Securities Total Realized gains on securites Net unrealized gain and loss related to securities, before tax Gross Unrealized Gains Available-for-sale Securities, Gross Unrealized Losses Gross Unrealized Losses Available for Sale Investment Securities Available for sale securities, pledged as collateral Average Interest Bearing Deposits in Federal Reserve Bank for Reserve Requirements Average deposits maintained to meet Federal Reserve Bank reserve requirements Average Recorded Investment In Impaired Loans And Interest Income That Would Have Been Recorded On Impaired Loan Average Recorded Investment in Impaired Loans and Interest Income that would have been Recorded on Nonperforming Loans Bank of Ireland Securities Services Bank of Ireland Securities Services (BoISS) Business Acquisition, Acquiree [Domain] Business Acquisition Business acquisition cash paid Business acquisition contingent consideration Business acquisition purchase price Business acquisition purchase price allocated to other intangible assets Business acquisition purchase price allocated to goodwill Business Combination, Contingent Consideration Arrangements, Agreement Period Business acquisition purchase price adjustment period Carrying (Reported) Amount, Fair Value Disclosure Increase in Cash and Due from Banks Increase in Cash and Due from Banks Cash and Due from Banks Cash and Due from Banks at End of Period Cash and Due from Banks at Beginning of Year Additional cash collateral deposited with derivative counterparties not offset against derivative assets and liabilities on the consolidated balance sheet as amounts exceed the net derivative positions with the counterparties. This amount represents additional cash collateral deposited with derivative counterparties not offset against derivative assets and liabilities Reduction in derivative assets (liabilities) due to cash collateral received from (deposited with) derivative counterparties. Reduction in derivative assets (liabilities) due to cash collateral received from (deposited with) derivative counterparties Reduction in derivatives due to cash collateral received from and deposited with derivative counterparties Additional cash collateral received from derivative counterparties not offset against derivative assets and liabilities on the consolidated balance sheet as amounts exceed the net derivative positions with the counterparties. This amount represents additional cash collateral received from derivative counterparties not offset against derivative assets and liabilities Cash Flow Hedge Gain (Loss) Reclassified to Compensation Expense, Net Cash Flow Hedge Gain (Loss) Reclassified to Compensation Expense, Net Compensation Cash Flow Hedge Gain (Loss) Reclassified to Employee Benefits, Net Cash Flow Hedge Gain (Loss) Reclassified to Employee Benefits, Net Employee Benefits Cash Flow Hedge Gain (Loss) Reclassified to Equipment and Software Expense, Net Cash Flow Hedge Gain (Loss) Reclassified to Equipment and Software Expense, Net Equipment and Software Cash Flow Hedge Gain (Loss) Reclassified to Interest Expense, Net Interest Expense Cash Flow Hedge Gain (Loss) Reclassified to Interest Income, Net Cash Flow Hedge Gain (Loss) Reclassified to Interest Income, Net Interest Income Cash Flow Hedge Gain (Loss) Reclassified to Occupancy Expense, Net Occupancy Expense Other Operating Expense Cash Flow Hedge Gain (Loss) Reclassified to Other Income, Net Other Operating Income Cash Flow Hedge Gain (Loss) Reclassified to Revenue, Net Trust, Investment and Other Servicing Fees Cash Flow Hedges Categories Of Loan And Commitments Categories Of Loan And Commitments Categories Of Loan And Commitments [Domain] Categories Of Loan And Commitments [Domain] Certificates of Deposit Changes recorded in the fair value of the hedged items in a fair value hedge Class of Stock [Domain] Client Related And Trading Client Related and Trading This represents other collection items presented on behalf of custody clients. Client Security Settlement Receivables Collateral deposited with derivative counterparties for derivatives instruments with credit-risk-related contigent features that are in a liability position Collateral from agreements to resell securities purchased transactions that has been repledged or sold. Amount of securities repledged or sold collateral Collateral Requirements Collateral Requirements Commercial And Institutional Loans Commercial and Institutional Commercial Loans Commercial Loans and Loan Commitments Commercial Loans and Loan Commitments Commercial Other Financing Receivable Other Other Commercial Commercial Real Estate Commercial Real Estates Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Commitments, Fair Value Disclosure Loan Commitments Common Stock Common Stock, Par Value Common Stock, Authorized Common Stock, Outstanding Common Stock, $1.66 2/3 Par Value; Authorized 560,000,000 shares; Outstanding shares of 240,996,807 and 242,268,903 Community Reinvestment Act CRA Community Reinvestment Act CRA Components of Accumulated Other Comprehensive Income Components of Accumulated Other Comprehensive Income Components of Accumulated Other Comprehensive Income [Domain] Components of Accumulated Other Comprehensive Income [Domain] Composition of Loan Portfolio [Line Items] Composition of Loan Portfolio [Line Items] Composition of Loan Portfolio [Table] Composition of Loan Portfolio [Table] Comprehensive Income Comprehensive Income Comprehensive Income (Loss) Note Accumulated Other Comprehensive Income (Loss) Corporate and Institutional Service Corporate and Institutional Services Corporate Debt Cost and Fair Value of Marketable Securities Amortized Cost and Fair Values of Securities Remaining Visa shares held by Northern Trust, original cost basis Credit Default Swap Contracts Exposure to indemnifications on credit losses from securities custody activities as of balance sheet date. Credit loss liability Credit Related Impairment Losses Recognized In Earnings On Other Than Temporarily Impaired Securities Credit-Related Losses Recognized in Earnings on Debt Securities Other-than-temporarily Impaired Net maximum amount of termination payments that could have been required for derivative instruments with credit risk-related contingent features that were in a liability position. Termination payments that could have been required for derivative instruments with credit-risk-related contingent features Available For Sale Debt Securities Held for Which Other-Than-Temporary-Impairment Loss Had been Recognized In the Year or Previously. Debt Securities Held for which an Other-Than-Temporary Impairment Loss has been Recognized in the Current Period or Previously Current Fiscal Year End Date Debt Disclosure [Line Items] Debt Disclosure [Line Items] Debt Disclosure [Table] Debt Disclosure [Table] Debt Issuance Debt Instrument Credit Rating Stated amount Stated interest rate Debt Instrument, Issuance Discount Rate Discount rate Maturity Debt Instrument, Name [Domain] Debt Security Default roll rates used to develop the expected loss on subprime and Alt-A portfolios. Expected loss on subprime, Alt-A, prime and 2nd lien portfolios developed using default roll rate Defined Benefit Plan, Amortization [Abstract] Amortization Net Loss Net Loss Prior Service Cost Defined Benefit Plan, Curtailment (Gain) Loss Gain on Curtailment of Non-U.S. Plan Expected Return on Plan Assets Expected Return on Plan Assets Interest Cost Net Periodic Benefit Expense (Benefit) Net Periodic Benefit Expense (Benefit) Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Service Cost Demand, Noninterest-Bearing, and Savings and Money Market Total Deposits Total Deposits Deposits [Abstract] Deposits Savings and Money Market Depreciation on Buildings and Equipment Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments. Derivative Asset Position, Fair Value Derivatives Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, excluding the effects of master netting arrangements. Derivative Assets, Fair Value Assets This represents reductions in the amounts of derivative assets recorded as a result of master netting agreements in place. Derivative assets recorded on the consolidated balance sheet, reduced as a result of master netting agreements Derivative, by Nature Derivative Contract Type [Domain] Asset Fair Value Fair Value Asset Fair Value Liability Liability Fair Value Derivative Financial Instruments, Assets Derivative Financial Instruments, Liabilities, Fair Value Disclosure Derivatives Derivative Financial Instruments, Liabilities Derivative Instrument Risk Derivative Instruments and Hedging Activities Disclosure [Line Items] Derivative Instruments and Hedging Activities Disclosure [Line Items] Derivative Instruments and Hedging Activities Disclosure [Table] Derivative Instruments and Hedging Activities Disclosure [Table] Derivative Financial Instruments Derivative Instruments, Gain (Loss) by Hedging Relationship Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) by Income Statement Location Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Total Net Gain/(Loss) Reclassified from AOCI to Earnings Amount of Derivative Gain/(Loss) Recognized in Income Amount Recognized in Income Hedging Instrument Gain/(Loss) Recognized in AOCI (Before Tax) Net Gain/(Loss) Recognized in AOCI Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, excluding the effects of master netting arrangements. Derivative Liabilities, Fair Value Liabilities This represents reductions in the amounts of derivative liabilities recorded as a result of master netting agreements in place. Derivative liabilities recorded on the consolidated balance sheet, reduced as a result of master netting agreements Derivative [Line Items] Derivative, Name [Domain] Aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a liability position Derivatives, by Derivative Instrument Contract Derivatives, by Derivative Instrument Contract Derivatives, by Derivative Instrument Contract [Domain] Derivatives, by Derivative Instrument Contract [Domain] Derivative [Table] Recent Accounting Pronouncements Designated as Hedging Instrument Disclosure - Amortized Cost and Fair Values of Securities [Abstract] Disclosure - Amortized Cost and Fair Values of Securities [Abstract] Disclosure - Amounts Outstanding in Selected Loan Categories [Abstract] Disclosure - Amounts Outstanding in Selected Loan Categories [Abstract] Disclosure - Assets and Liabilities Measured at Fair Value on a Recurring Basis Segregated by Fair Value Hierarchy Level [Abstract] Disclosure - Assets and Liabilities Measured at Fair Value on a Recurring Basis Segregated by Fair Value Hierarchy Level [Abstract] Disclosure - Assets Measured at Fair Value on a Nonrecurring Basis [Abstract] Disclosure - Assets Measured at Fair Value on a Nonrecurring Basis [Abstract] Disclosure - Average Recorded Investment in Impaired Loans and Interest Income that would have been Recorded on Nonperforming Loans [Abstract] Disclosure - Average Recorded Investment in Impaired Loans and Interest Income that would have been Recorded on Nonperforming Loans [Abstract] Disclosure - Balances and Delinquency Status of Performing and Nonperforming Loans and Leases by Segment and Class as well as Total Other Real Estate Owned and Nonperforming Asset [Abstract] Disclosure - Balances and Delinquency Status of Performing and Nonperforming Loans and Leases by Segment and Class as well as Total Other Real Estate Owned and Nonperforming Asset [Abstract]