Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Servicing fees	$ 5,167	$ 5,074	$ 5,421
Management fees	1,880	1,824	1,899
Foreign exchange trading services	1,363	1,058	1,153
Securities finance	356	471	543
Software and processing fees	733	720	438
Total fee revenue	9,499	9,147	9,454
Net interest income	2,200	2,566	2,671
Total other income	4	43	6
Total revenue	11,703	11,756	12,131
Provision for credit losses	88	10	15
Total expenses	8,716	9,034	9,015
Income before income taxes	$ 2,899	$ 2,712	$ 3,101
Pre-tax margin	25.00%	23.00%	26.00%
Average assets (in billions)	$ 269,300	$ 223,300	$ 223,400
Operating Segments
Segment Reporting Information [Line Items]
Management fees	1,880
Foreign exchange trading services	64
Securities finance	14
Software and processing fees	27
Net interest income	(11)
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees	5,167	5,074	5,429
Management fees	0	0	0
Foreign exchange trading services	1,299	974	1,071
Securities finance	342	462	543
Software and processing fees	706	691	443
Total fee revenue	7,514	7,201	7,486
Net interest income	2,211	2,590	2,691
Total other income	4	43	6
Total revenue	9,729	9,834	10,183
Provision for credit losses	88	10	15
Total expenses	7,071	7,140	7,081
Income before income taxes	$ 2,570	$ 2,684	$ 3,087
Pre-tax margin	26.00%	27.00%	30.00%
Average assets (in billions)	$ 266,400	$ 220,300	$ 220,200
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
Servicing fees	0	0	0
Management fees	1,880	1,824	1,899
Foreign exchange trading services	64	84	82
Securities finance	14	9	0
Software and processing fees	27	29	(5)
Total fee revenue	1,985	1,946	1,976
Net interest income	(11)	(24)	(20)
Total other income	0	0	0
Total revenue	1,974	1,922	1,956
Provision for credit losses	0	0	0
Total expenses	1,471	1,535	1,544
Income before income taxes	$ 503	$ 387	$ 412
Pre-tax margin	25.00%	20.00%	21.00%
Average assets (in billions)	$ 2,900	$ 3,000	$ 3,200
Other
Segment Reporting Information [Line Items]
Servicing fees	0	0	(8)
Management fees	0	0	0
Foreign exchange trading services	0	0	0
Securities finance	0	0	0
Software and processing fees	0	0	0
Total fee revenue	0	0	(8)
Net interest income	0	0	0
Total other income	0	0	0
Total revenue	0	0	(8)
Provision for credit losses	0	0	0
Total expenses	174	359	390
Income before income taxes	$ (174)	$ (359)	$ (398)