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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	$ 36,184	$ 26,977
Reduction in estimated fair value of interest rate contracts in asset position	(686)	(783)
Reduction in estimated fair value of interest rate contracts in liability position	(15)	(32)
Unrealized gain recognized in other comprehensive income related to cash flow hedges	135
Aggregate fair value of derivative financial instruments in asset position	157	179
Collateral relating to net asset positions	157	179
Fair Value Hedges
Derivative [Line Items]
Impact of estimated fair value gain (losses) on hedging instruments	153	43
Cash Flow Hedges
Derivative [Line Items]
Impact of estimated fair value gain (losses) on hedging instruments	136	214
Clearinghouse Credit Facilities
Derivative [Line Items]
Amount of initial margin posted	257	129
Interest rate swap agreements
Derivative [Line Items]
Increase decrease in net interest income due to interest rate swap agreements	(414)	$ (302)	$ (26)
Notional amounts of derivative contracts entered into for trading account purposes	$ 36,184
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest and Dividend Income, Operating	Interest and Dividend Income, Operating	Interest and Dividend Income, Operating
Interest rate swap agreements | 2025
Derivative [Line Items]
Unrealized gain recognized in other comprehensive income related to cash flow hedges	$ (47)
Interest rate swap agreements | 2026
Derivative [Line Items]
Unrealized gain recognized in other comprehensive income related to cash flow hedges	(49)
Interest rate swap agreements | 2027
Derivative [Line Items]
Unrealized gain recognized in other comprehensive income related to cash flow hedges	6
Interest rate swap agreements | 2028
Derivative [Line Items]
Unrealized gain recognized in other comprehensive income related to cash flow hedges	(45)
Cash Flow Hedges
Derivative [Line Items]
Increase decrease in net interest income due to interest rate swap agreements	(364)	$ (250)	$ (36)
Interest Rate Contracts
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	40,500	44,400
Foreign Currency and Other Option and Futures Contracts
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	1,600	1,500
Forward-Starting Interest Rate Swap Agreements | Fair Value Hedges
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	3,400	1,000
Forward-Starting Interest Rate Swap Agreements | Cash Flow Hedges
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	$ 10,000	$ 9,000

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The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

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Fair value of securities received as collateral against derivative assets.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Indicates line item in statement of income or comprehensive income that includes gain (loss) from effective portion of derivative instrument reclassified from accumulated other comprehensive income (AOCI) into income.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

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