Derivative Instruments - Effect of Fair Value and Cash Flow Hedge Accounting on Consolidated Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Interest Income	$ 7,927	$ 8,086	$ 23,047	$ 23,835
Interest Expense	3,705	3,951	10,682	11,692
Losses recognized in earnings related discontinuance of cash flow hedges	5	7	19	21
Asset and Liability Management Positions | Fair value hedges | Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, fair value hedged item	(34)	1,113	699	666
Asset and Liability Management Positions | Fair value hedges | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, fair value hedged item	92	303	(96)	315
Asset and Liability Management Positions | Fair value hedges | Interest rate contracts | Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, fair value hedging instruments	34	(1,108)	(699)	(663)
Asset and Liability Management Positions | Fair value hedges | Interest rate contracts | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, fair value hedging instruments	(92)	(302)	92	(314)
Asset and Liability Management Positions | Cash flow hedges | Interest rate contracts | Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, cash flow hedging instruments	(60)	(70)	(172)	(185)
Asset and Liability Management Positions | Cash flow hedges | Interest rate contracts | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in earnings, cash flow hedging instruments	$ (5)	$ (7)	$ (19)	$ (21)