Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives			$ (345)	$ (18)
Interest rate risks | Derivatives designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ 13	$ 15	42	46
Interest rate risks | Derivatives designated as hedging instruments | Reclassification out of Accumulated Other Comprehensive Income | Interest income - loans
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	14	16	43	47
Interest rate risks | Derivatives designated as hedging instruments | Change In Fair Value Of Interest Rate Swaps Hedging Investment Securities | Interest income - loans
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(2)	5	384	18
Interest rate risks | Derivatives designated as hedging instruments | Change In Fair Value Of Hedged Investment Securities | Interest income - loans
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	1	(6)	(385)	(19)
Currency exchange risk | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(4)	0	(5)	0
Currency exchange risk | Derivatives not designated as hedging instruments | Revaluations of internal foreign currency instruments, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	47	(14)	26	(35)
Currency exchange risk | Derivatives not designated as hedging instruments | Foreign exchange forward contracts, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(51)	14	(31)	35
Other derivative instruments | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	10	(4)	12	1
Other derivative instruments | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	2	2	8	4
Other derivative instruments | Derivatives not designated as hedging instruments | Revaluations of internal foreign currency instruments, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	12	1	7	16
Other derivative instruments | Derivatives not designated as hedging instruments | Foreign exchange forward contracts, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(2)	(5)	5	(15)
Total return swaps | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(2)	0	25	0
Equity warrant assets | Derivatives not designated as hedging instruments | Gains on equity warrant assets, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ 40	$ 147	$ 120	$ 491