Reportable Operating Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total non-interest revenues	$ 11,939	$ 10,978	$ 35,186	$ 31,549
Revenue from contracts with customers	9,377	8,733	27,656	25,144
Interest income	5,240	3,374	14,431	8,693
Interest expense	1,798	796	4,901	1,556
Total revenues net of interest expense	15,381	13,556	44,716	38,686
Pretax income (loss)	3,100	2,459	8,001	7,714
Total assets	250,587	215,000	250,587	215,000	$ 228,354
Corporate and Other
Segment Reporting Information [Line Items]
Total non-interest revenues	(44)	(28)	(94)	(28)
Revenue from contracts with customers	(8)	(13)	(28)	14
Interest income	579	201	1,571	330
Interest expense	603	240	1,643	391
Total revenues net of interest expense	(68)	(67)	(166)	(89)
Pretax income (loss)	(709)	(582)	(1,821)	(1,589)
Total assets	36,000	31,000	36,000	31,000
USCS | Operating Segments
Segment Reporting Information [Line Items]
Total non-interest revenues	4,680	4,233	13,682	12,024
Revenue from contracts with customers	3,464	3,200	10,182	9,139
Interest income	3,228	2,251	8,937	5,880
Interest expense	700	274	1,898	513
Total revenues net of interest expense	7,208	6,210	20,721	17,391
Pretax income (loss)	1,584	1,309	3,964	4,114
Total assets	98,000	85,000	98,000	85,000
CS | Operating Segments
Segment Reporting Information [Line Items]
Total non-interest revenues	3,257	3,145	9,665	8,986
Revenue from contracts with customers	2,864	2,791	8,505	8,003
Interest income	881	552	2,379	1,435
Interest expense	391	201	1,076	409
Total revenues net of interest expense	3,747	3,496	10,968	10,012
Pretax income (loss)	852	774	2,195	2,333
Total assets	57,000	51,000	57,000	51,000
ICS | Operating Segments
Segment Reporting Information [Line Items]
Total non-interest revenues	2,390	2,066	7,006	6,065
Revenue from contracts with customers	1,558	1,332	4,527	3,857
Interest income	538	364	1,502	1,035
Interest expense	285	178	770	445
Total revenues net of interest expense	2,643	2,252	7,738	6,655
Pretax income (loss)	387	166	829	593
Total assets	39,000	33,000	39,000	33,000
GMNS | Operating Segments
Segment Reporting Information [Line Items]
Total non-interest revenues	1,656	1,562	4,927	4,502
Revenue from contracts with customers	1,499	1,423	4,470	4,131
Interest income	14	6	42	13
Interest expense	(181)	(97)	(486)	(202)
Total revenues net of interest expense	1,851	1,665	5,455	4,717
Pretax income (loss)	986	792	2,834	2,263
Total assets	$ 21,000	$ 15,000	$ 21,000	$ 15,000