Derivative Instruments and Hedging Activities - Effect of Fair Value Hedge Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest income, receipts	$ 2	$ 20	$ 34	$ 36
Interest expense, receipts	(20)		(44)
Interest rate swaps \| Interest Revenue
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivatives designated as hedging instruments	3	(214)	(252)	(19)
Interest rate swaps \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivatives designated as hedging instruments	(4)	0	14	0
Debt Securities and Hedged Available-for-Sale Securities \| Interest Revenue
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged items	(3)	216	252	19
Long-term debt (3) \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged items	$ 4	$ 0	$ (12)	$ 0

Interest Expense, Fair Value Hedge Derivative Instrument, Increase (Decrease)

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- Definition

Interest Income, Fair Value Hedge Derivative Instrument, Increase (Decrease)

+ References

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- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

+ References

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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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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