Derivative Instruments - Effect of Fair Value Hedge Accounting (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative [Line Items]
Mortgage loans	$ 39,962	$ 38,344	$ 118,161	$ 113,436
Interest Expense: Long-Term Debt	(33,740)	(32,639)	(99,631)	(96,702)
Interest Income: Mortgage Loans \| Income Statement Location [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases
Derivative [Line Items]
Hedged items	(3,133)	100	(3,626)	747
Discontinued hedge related basis adjustment amortization	44	6	71	29
Derivatives designated as hedging instruments	3,116	(89)	3,580	(732)
Interest accruals on hedging instruments	(13)	61	(9)	170
Gains (losses) recognized in net interest income on fair value hedging relationships	14	78	16	214
Interest Expense: Long-Term Debt \| Income Statement Location [Axis]: us-gaap:InterestExpenseLongTermDebt
Derivative [Line Items]
Hedged items	393	15	726	(259)
Discontinued hedge related basis adjustment amortization	(173)	(193)	(502)	(633)
Derivatives designated as hedging instruments	(378)	(20)	(708)	258
Interest accruals on hedging instruments	(3)	(25)	(13)	(70)
Gains (losses) recognized in net interest income on fair value hedging relationships	$ (161)	$ (223)	$ (497)	$ (704)

Discontinued hedge related basis adjustment amortization

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- Definition

Interest Accruals On Hedging Instruments

+ 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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-Topic 815
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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.

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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.

+ References

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- Definition

Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ References

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- Definition

The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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- Definition

Aggregate amount of interest paid or due on all long-term debt.

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