Derivative Financial Instruments - Carrying Amount and Cumulative Basis Adjustments for Hedge Accounting (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Prepayable financial asset closed portfolio, amortized cost	$ 3,590	$ 3,320
Prepayable financial asset closed portfolio, last-of-layer, amortized cost	1,820	1,820
Cumulative adjustment associated with hedging relationships	29	(26)
Hedged Items Currently Designated \| Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Assets/Liabilities	15,056	15,951
Cumulative Hedge Accounting Basis Adjustments	(47)	(323)
Hedged Items Currently Designated \| Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Assets/Liabilities	21,855	18,666
Cumulative Hedge Accounting Basis Adjustments	85	(376)
De-designated \| Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative Hedge Accounting Basis Adjustments	77	103
De-designated \| Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative Hedge Accounting Basis Adjustments	$ 0	$ 1

Cumulative Adjustment Associated with Hedging Relationships

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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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- Definition

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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