Derivatives and Hedging Activities - Schedule of Effect of Fair Value and Cash Flow Hedges on Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense — Long-term debt	$ (328)	$ (275)
Interest income – loans	1,538	1,476
Interest Income - securities	232	194
Investment banking and debt placement fees	170	145
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(215)	(216)
Interest rate \| Interest expense – long-term debt \| Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items	128	(155)
Recognized on derivatives designated as hedging instruments	(200)	108
Net income (expense) recognized on fair value hedges	(72)	(47)
Interest rate \| Interest expense – long-term debt \| Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	0	(1)
Net income (expense) recognized on cash flow hedges	0	(1)
Interest rate \| Interest income – loans \| Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items	0	0
Recognized on derivatives designated as hedging instruments	0	0
Net income (expense) recognized on fair value hedges	0	0
Interest rate \| Interest income – loans \| Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(216)	(215)
Net income (expense) recognized on cash flow hedges	(216)	(215)
Interest rate \| Interest Income - securities \| Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items	(151)	6
Recognized on derivatives designated as hedging instruments	182	(2)
Net income (expense) recognized on fair value hedges	31	4
Interest rate \| Interest Income - securities \| Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	0	0
Net income (expense) recognized on cash flow hedges	0	0
Interest rate \| Investment banking and debt placement fees \| Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items	0	0
Recognized on derivatives designated as hedging instruments	0	0
Net income (expense) recognized on fair value hedges	0	0
Interest rate \| Investment banking and debt placement fees \| Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	1	0
Net income (expense) recognized on cash flow hedges	$ 1	$ 0

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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.

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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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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Interest and fee income generated by loans the Entity intends and has the 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: (1) industrial and agricultural; (2) real estate; and (3) real estate construction loans; (4) trade financing; (5) lease financing; (6) home equity lines-of-credit; (7) automobile and other vehicle loans; and (8) credit card and other revolving-type loans. Also includes interest income for leases held by the Entity.

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

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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