Derivative Financial Instruments - Carrying Amount and Cumulative Basis Adjustments for Hedge Accounting (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Prepayable financial asset closed portfolio, amortized cost	$ 2,690	$ 3,300
Prepayable financial asset closed portfolio, last-of-layer, amortized cost	1,430	1,730
Cumulative adjustment associated with hedging relationships	6	21
Hedged Items Currently Designated \| Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Assets/Liabilities	16,302	15,553
Cumulative Hedge Accounting Basis Adjustments	(244)	(76)
Hedged Items Currently Designated \| Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Assets/Liabilities	23,512	22,804
Cumulative Hedge Accounting Basis Adjustments	(188)	99
De-designated \| Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative Hedge Accounting Basis Adjustments	64	72
De-designated \| Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative Hedge Accounting Basis Adjustments	$ 0	$ 0

Cumulative Adjustment Associated with Hedging Relationships

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- Definition

Prepayable Financial Asset Closed Portfolio, Amortized Cost

+ References

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- Definition

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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- Definition

Amount of asset hedged in fair value hedging relationship.

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Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk. Excludes cumulative basis adjustment related to foreign exchange risk.

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- Definition

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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