Revenue from Contracts with Customers - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,937	$ 2,873	$ 6,002	$ 5,805
Servicing fees	1,272	1,252	2,559	2,503
Management fees	425	441	874	861
Foreign exchange trading services	344	273	803	553
Securities finance	92	126	184	244
Software and processing fees	245	168	357	359
Total fee revenue	2,378	2,260	4,777	4,520
Net interest income	559	613	1,223	1,286
Total fee revenue	0	0	2	(1)
Operating Segments | Investment Servicing
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,581	1,513	3,132	3,036
All other revenue	891	887	1,952	1,836
Total revenue	2,472	2,400	5,084	4,872
Servicing fees	1,272	1,252	2,559	2,503
Management fees	0	0	0	0
Foreign exchange trading services	312	240	746	486
Securities finance	88	122	177	239
Software and processing fees	229	163	366	343
Total fee revenue	1,901	1,777	3,848	3,571
Net interest income	571	623	1,234	1,302
Total fee revenue			2	(1)
Operating Segments | Investment Servicing | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,272	1,252	2,559	2,503
All other revenue	0	0	0	0
Servicing fees	1,272	1,252	2,559	2,503
Operating Segments | Investment Servicing | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	0	0	0	0
Management fees	0	0	0	0
Operating Segments | Investment Servicing | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	95	82	195	168
All other revenue	217	158	551	318
Foreign exchange trading services	312	240	746	486
Operating Segments | Investment Servicing | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	63	75	120	145
All other revenue	25	47	57	94
Securities finance	88	122	177	239
Operating Segments | Investment Servicing | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	151	104	258	220
All other revenue	78	59	108	123
Software and processing fees	229	163	366	343
Operating Segments | Investment Servicing | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,581	1,513	3,132	3,036
All other revenue	320	264	716	535
Total fee revenue	1,901	1,777	3,848	3,571
Operating Segments | Investment Servicing | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	571	623	1,234	1,302
Net interest income	571	623	1,234	1,302
Operating Segments | Investment Servicing | Total other income
Disaggregation of Revenue [Line Items]
Topic 606 revenue			0	0
All other revenue			2	(1)
Total fee revenue			2	(1)
Operating Segments | Investment Management
Disaggregation of Revenue [Line Items]
Topic 606 revenue	457	474	931	928
All other revenue	8	(1)	(13)	5
Total revenue	465	473	918	933
Servicing fees	0	0	0	0
Management fees	425	441	874	861
Foreign exchange trading services	32	33	57	67
Securities finance	4	4	7	5
Software and processing fees	16	5	(9)	16
Total fee revenue	477	483	929	949
Net interest income	(12)	(10)	(11)	(16)
Total fee revenue			0	0
Operating Segments | Investment Management | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	0	0	0	0
Servicing fees	0	0	0	0
Operating Segments | Investment Management | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	425	441	874	861
All other revenue	0	0	0	0
Management fees	425	441	874	861
Operating Segments | Investment Management | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	32	33	57	67
All other revenue	0	0	0	0
Foreign exchange trading services	32	33	57	67
Operating Segments | Investment Management | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	4	4	7	5
Securities finance	4	4	7	5
Operating Segments | Investment Management | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	16	5	(9)	16
Software and processing fees	16	5	(9)	16
Operating Segments | Investment Management | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	457	474	931	928
All other revenue	20	9	(2)	21
Total fee revenue	477	483	929	949
Operating Segments | Investment Management | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	(12)	(10)	(11)	(16)
Net interest income	$ (12)	$ (10)	(11)	(16)
Operating Segments | Investment Management | Total other income
Disaggregation of Revenue [Line Items]
Topic 606 revenue			0	0
All other revenue			0	0
Total fee revenue			$ 0	$ 0