Revenue from Contracts with Customers - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 3,065	$ 2,932
Servicing fees	1,287	1,251
Management fees	449	420
Foreign exchange trading services	459	280
Securities finance	92	118
Software and processing fees	112	191
Total fee revenue	2,399	2,260
Net interest income	664	673
Total fee revenue	2	(1)
Operating Segments | Investment Servicing
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,551	1,523
All other revenue	1,061	949
Total revenue	2,612	2,472
Servicing fees	1,287	1,251
Management fees	0	0
Foreign exchange trading services	434	246
Securities finance	89	117
Software and processing fees	137	180
Total fee revenue	1,947	1,794
Net interest income	663	679
Total fee revenue	2	(1)
Operating Segments | Investment Servicing | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,287	1,251
All other revenue	0	0
Servicing fees	1,287	1,251
Operating Segments | Investment Servicing | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	0	0
Management fees	0	0
Operating Segments | Investment Servicing | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	100	86
All other revenue	334	160
Foreign exchange trading services	434	246
Operating Segments | Investment Servicing | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	57	70
All other revenue	32	47
Securities finance	89	117
Operating Segments | Investment Servicing | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	107	116
All other revenue	30	64
Software and processing fees	137	180
Operating Segments | Investment Servicing | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,551	1,523
All other revenue	396	271
Total fee revenue	1,947	1,794
Operating Segments | Investment Servicing | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	663	679
Net interest income	663	679
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	474	454
All other revenue	(21)	6
Total revenue	453	460
Servicing fees	0	0
Management fees	449	420
Foreign exchange trading services	25	34
Securities finance	3	1
Software and processing fees	(25)	11
Total fee revenue	452	466
Net interest income	1	(6)
Total fee revenue	0	0
Operating Segments | Investment Management | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	0	0
Servicing fees	0	0
Operating Segments | Investment Management | Management fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	449	420
All other revenue	0	0
Management fees	449	420
Operating Segments | Investment Management | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	25	34
All other revenue	0	0
Foreign exchange trading services	25	34
Operating Segments | Investment Management | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	3	1
Securities finance	3	1
Operating Segments | Investment Management | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	(25)	11
Software and processing fees	(25)	11
Operating Segments | Investment Management | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	474	454
All other revenue	(22)	12
Total fee revenue	452	466
Operating Segments | Investment Management | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0
All other revenue	1	(6)
Net interest income	1	(6)
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