Derivative Financial Instruments - Fair Value Hedges Basis Adjustments (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Closed portfolio of securities hedged, amortized cost	$ 19,400	$ 27,400
Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Closed portfolio of securities hedged, amortized cost	14,800	16,400
Fair Value Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of the Hedged Liability	28,633	28,194
Fair Value Hedges \| Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged liability	(354)	70
Fair Value Hedges \| Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged liability	(305)	(375)
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:AvailableForSaleSecuritiesDebtSecurities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of the Hedged Assets	38,106	38,608
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:AvailableForSaleSecuritiesDebtSecurities \| Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged assets	(148)	104
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:AvailableForSaleSecuritiesDebtSecurities \| Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged assets	(27)	13
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of the Hedged Assets	174	179
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss \| Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged assets	0	0
Fair Value Hedges \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss \| Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustment increasing (decreasing) the carrying amount of the hedged assets	$ 2	$ 3

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of asset hedged in fair value hedging relationship.

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Amortized cost of closed portfolio of financial asset used to designate hedging relationship in which hedged item is expected to be outstanding for designated hedged period.

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