Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 305	$ 35	$ 472	$ 81
Gains on equity warrant assets, net	122	27	344	40
Client investment fees	15	32	35	75
Foreign exchange fees	67	36	124	84
Credit card fees	31	21	59	50
Deposit service charges	28	21	53	45
Lending related fees	18	11	34	24
Letters of credit and standby letters of credit fees	13	11	26	23
Investment banking revenue	103	142	245	188
Commissions	17	17	41	33
Other	42	16	72	27
Total noninterest income	$ 761	$ 369	$ 1,505	$ 670