Derivative Financial Instruments - Amounts Related to Derivative Instruments Not Designated as Hedges (Details) - Not designated as hedges - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	$ (275)	$ 84	$ 134	$ (80)
Client-related and other risk management: \| Interest rate contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	18	21	76	42
Client-related and other risk management: \| Foreign exchange contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	46	69	167	(144)
Client-related and other risk management: \| Equity contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	(89)	24	161	39
Client-related and other risk management: \| Credit contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	(19)	(1)	(30)	(13)
Client-related and other risk management: \| Commodity contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	4	2	10	8
MSRs and mortgage banking: \| Interest rate contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:NoninterestIncome
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) recognized in income	$ (235)	$ (31)	$ (250)	$ (12)