Revenue from Contracts with Customers - Disaggregation of Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [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
Total revenue	11,703	11,756	12,131
Total other income	4	43	6
Operating Segments
Disaggregation of Revenue [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
Disaggregation of Revenue [Line Items]
Topic 606 revenue	6,243	6,135	6,307
All other revenue	3,486	3,699	3,876
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 revenue	9,729	9,834	10,183
Total other income	4	43	6
Operating Segments | Investment Servicing | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	5,167	5,074	5,429
All other revenue	0	0	0
Servicing fees	5,167	5,074	5,429
Operating Segments | Investment Servicing | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Management fees	0	0	0
Operating Segments | Investment Servicing | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	377	346	361
All other revenue	922	628	710
Foreign exchange trading services	1,299	974	1,071
Operating Segments | Investment Servicing | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	212	259	308
All other revenue	130	203	235
Securities finance	342	462	543
Operating Segments | Investment Servicing | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	487	456	209
All other revenue	219	235	234
Software and processing fees	706	691	443
Operating Segments | Investment Servicing | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	6,243	6,135	6,307
All other revenue	1,271	1,066	1,179
Total fee revenue	7,514	7,201	7,486
Operating Segments | Investment Servicing | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	2,211	2,590	2,691
Net interest income	2,211	2,590	2,691
Operating Segments | Investment Servicing | Total other income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	4	43	6
Total other income	4	43	6
Operating Segments | Investment Management
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,944	1,908	1,981
All other revenue	30	14	(25)
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 revenue	1,974	1,922	1,956
Total other income	0	0	0
Operating Segments | Investment Management | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Servicing fees	0	0	0
Operating Segments | Investment Management | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,880	1,824	1,899
All other revenue	0	0	0
Management fees	1,880	1,824	1,899
Operating Segments | Investment Management | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	64	84	82
All other revenue	0	0	0
Foreign exchange trading services	64	84	82
Operating Segments | Investment Management | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	14	9	0
Securities finance	14	9	0
Operating Segments | Investment Management | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	27	29	(5)
Software and processing fees	27	29	(5)
Operating Segments | Investment Management | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,944	1,908	1,981
All other revenue	41	38	(5)
Total fee revenue	1,985	1,946	1,976
Operating Segments | Investment Management | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	(11)	(24)	(20)
Net interest income	(11)	(24)	(20)
Operating Segments | Investment Management | Total other income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Total other income	0	0	0
Other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	(8)
All other revenue	0	0	0
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 revenue	0	0	(8)
Total other income	0	0	0
Other | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	(8)
All other revenue	0	0	0
Servicing fees	0	0	(8)
Other | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Management fees	0	0	0
Other | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Foreign exchange trading services	0	0	0
Other | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Securities finance	0	0	0
Other | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Software and processing fees	0	0	0
Other | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	(8)
All other revenue	0	0	0
Total fee revenue	0	0	(8)
Other | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Net interest income	0	0	0
Other | Total other income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0
All other revenue	0	0	0
Total other income	$ 0	$ 0	$ 0