Business segments - Contribution of Segments to Overall Profitability (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Total fee and other revenue	$ 3,353	$ 3,430	$ 3,394	$ 10,011	$ 9,975
Net interest revenue (expense)	926	824	641	2,448	1,941
Provision for credit losses	(30)	47	(45)	19	(214)
Noninterest expense	3,679	3,112	2,918	9,797	8,547
Net income (loss) attributable to noncontrolling interests	0	(5)	(4)	(13)	6
Operating segments
Segment Reporting Information [Line Items]
Total fee and other revenue	3,353	3,435	3,398	10,024	9,969
Net interest revenue (expense)	926	824	641	2,448	1,941
Total revenue (loss)	4,279	4,259	4,039	12,472	11,910
Provision for credit losses	(30)	47	(45)	19	(214)
Noninterest expense	3,679	3,112	2,918	9,797	8,547
Income (loss) before income taxes	$ 630	$ 1,100	$ 1,166	$ 2,656	$ 3,577
Pre-tax operating margin	15.00%	26.00%	29.00%	21.00%	30.00%
Average assets	$ 415,670	$ 437,623	$ 446,761	$ 431,074	$ 453,106
Operating segments | Securities Services
Segment Reporting Information [Line Items]
Total fee and other revenue	1,536	1,549	1,488	4,488	4,352
Net interest revenue (expense)	538	457	349	1,372	1,059
Total revenue (loss)	2,074	2,006	1,837	5,860	5,411
Provision for credit losses	(6)	13	(19)	(3)	(127)
Noninterest expense	1,557	1,656	1,543	4,723	4,362
Income (loss) before income taxes	$ 523	$ 337	$ 313	$ 1,140	$ 1,176
Pre-tax operating margin	25.00%	17.00%	17.00%	19.00%	22.00%
Average assets	$ 203,063	$ 219,797	$ 226,930	$ 214,518	$ 228,714
Operating segments | Market and Wealth Services
Segment Reporting Information [Line Items]
Total fee and other revenue	989	974	890	2,869	2,707
Net interest revenue (expense)	378	340	283	1,014	861
Total revenue (loss)	1,367	1,314	1,173	3,883	3,568
Provision for credit losses	(1)	4	(16)	1	(64)
Noninterest expense	737	702	668	2,147	2,002
Income (loss) before income taxes	$ 631	$ 608	$ 521	$ 1,735	$ 1,630
Pre-tax operating margin	46.00%	46.00%	44.00%	45.00%	46.00%
Average assets	$ 138,204	$ 141,952	$ 143,630	$ 140,435	$ 145,562
Operating segments | Investment and Wealth Management
Segment Reporting Information [Line Items]
Total fee and other revenue	805	837	985	2,549	2,880
Net interest revenue (expense)	57	62	47	176	142
Total revenue (loss)	862	899	1,032	2,725	3,022
Provision for credit losses	3	0	(7)	0	(7)
Noninterest expense	1,356	691	691	2,802	2,077
Income (loss) before income taxes	$ (497)	$ 208	$ 348	$ (77)	$ 952
Pre-tax operating margin	(57.00%)	23.00%	34.00%	(3.00%)	31.00%
Average assets	$ 29,996	$ 33,668	$ 30,195	$ 33,077	$ 30,870
Net income (loss) attributable to noncontrolling interests	0	(5)	(4)	(13)	6
Operating segments | Other
Segment Reporting Information [Line Items]
Total fee and other revenue	23	75	35	118	30
Net interest revenue (expense)	(47)	(35)	(38)	(114)	(121)
Total revenue (loss)	(24)	40	(3)	4	(91)
Provision for credit losses	(26)	30	(3)	21	(16)
Noninterest expense	29	63	16	125	106
Income (loss) before income taxes	(27)	(53)	(16)	(142)	(181)
Average assets	$ 44,407	$ 42,206	$ 46,006	$ 43,044	$ 47,960