Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives			$ (121)	$ (7)
Interest rate risks | Derivatives designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ 15	$ 6	29	22
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	29	31
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	56	(14)	386	4
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	(55)	4	(386)	(13)
Currency exchange risk | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(4)	1	(1)	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	(23)	7	(21)	(21)
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	19	(6)	20	21
Other derivative instruments | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	5	5	2	5
Other derivative instruments | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	3	(2)	6	2
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	0	17	(5)	15
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	5	(12)	7	(10)
Total return swaps | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	35	0	27	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	$ 17	$ 122	$ 80	$ 344