Derivative Instruments and Hedging Activities - Effect of Fair Value Hedge Derivatives (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest income, receipts	$ 1	$ 18
Interest expense, receipts	5	(10)
Interest rate swaps \| Interest Revenue
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivatives designated as hedging instruments	31	(161)
Interest rate swaps \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivatives designated as hedging instruments	(107)	27
Debt Securities and Hedged Available-for-Sale Securities \| Interest Revenue
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged items	(31)	161
Long-term debt \| Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged items	$ 107	$ (25)

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

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- Definition

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

+ References

No definition available.

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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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- Definition

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

+ 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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