Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 189	$ 190	$ 661	$ 271
Gains on equity warrant assets, net	147	54	491	94
Client investment fees	20	32	55	107
Wealth management and trust fees	22	0	22	0
Foreign exchange fees	65	44	189	128
Credit card fees	34	23	93	72
Deposit service charges	29	22	82	67
Lending related fees	21	13	55	38
Letters of credit and standby letters of credit fees	13	12	39	35
Investment banking revenue	90	92	335	281
Commissions	17	16	58	49
Other	25	49	97	76
Total noninterest income	$ 672	$ 547	$ 2,177	$ 1,218