Revenue from Contracts with Customers - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Servicing fees	$ 1,252	$ 1,381	$ 2,503	$ 2,802
Management fees	441	465	861	937
Foreign exchange trading services	273	315	553	619
Securities finance	126	154	244	295
Processing fees and other	168	80	359	157
Total fee revenue	2,260	2,395	4,520	4,810
Net interest income	613	659	1,286	1,302
Gains (losses) related to investment securities, net	0	9	(1)	7
Total revenue	2,873	3,063	5,805	6,119
Servicing fees
Disaggregation of Revenue [Line Items]
Servicing fees	1,252	1,381	2,503	2,802
Management fees
Disaggregation of Revenue [Line Items]
Management fees	441	465	861	937
Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Foreign exchange trading services	273	315	553	619
Securities finance
Disaggregation of Revenue [Line Items]
Securities finance	126	154	244	295
Processing fees and other
Disaggregation of Revenue [Line Items]
Processing fees and other	168	80	359	157
Total fee revenue
Disaggregation of Revenue [Line Items]
Total fee revenue	2,260	2,395	4,520	4,810
Net interest income
Disaggregation of Revenue [Line Items]
Net interest income	613	659	1,286	1,302
Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Gains (losses) related to investment securities, net	0	9	(1)	7
Operating Segments | Investment Servicing
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,513	1,585	3,036	3,198
All other revenue	887	982	1,836	1,928
Servicing fees	1,252	1,381	2,503	2,802
Management fees	0	0	0	0
Foreign exchange trading services	240	282	486	555
Securities finance	122	154	239	295
Processing fees and other	163	78	343	156
Total fee revenue	1,777	1,895	3,571	3,808
Net interest income	623	663	1,302	1,311
Gains (losses) related to investment securities, net	0	9	(1)	7
Total revenue	2,400	2,567	4,872	5,126
Operating Segments | Investment Servicing | Servicing fees
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,252	1,381	2,503	2,802
All other revenue	0	0	0	0
Servicing fees	1,252	1,381	2,503	2,802
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	82	91	168	186
All other revenue	158	191	318	369
Foreign exchange trading services	240	282	486	555
Operating Segments | Investment Servicing | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	75	90	145	167
All other revenue	47	64	94	128
Securities finance	122	154	239	295
Operating Segments | Investment Servicing | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	104	23	220	43
All other revenue	59	55	123	113
Processing fees and other	163	78	343	156
Operating Segments | Investment Servicing | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	1,513	1,585	3,036	3,198
All other revenue	264	310	535	610
Total fee revenue	1,777	1,895	3,571	3,808
Operating Segments | Investment Servicing | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	623	663	1,302	1,311
Net interest income	623	663	1,302	1,311
Operating Segments | Investment Servicing | Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	0	9	(1)	7
Gains (losses) related to investment securities, net	0	9	(1)	7
Operating Segments | Investment Management
Disaggregation of Revenue [Line Items]
Topic 606 revenue	474	498	928	1,001
All other revenue	(1)	(2)	5	(8)
Servicing fees	0	0	0	0
Management fees	441	465	861	937
Foreign exchange trading services	33	33	67	64
Securities finance	4	0	5	0
Processing fees and other	5	2	16	1
Total fee revenue	483	500	949	1,002
Net interest income	(10)	(4)	(16)	(9)
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	473	496	933	993
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	441	465	861	937
All other revenue	0	0	0	0
Management fees	441	465	861	937
Operating Segments | Investment Management | Foreign exchange trading services
Disaggregation of Revenue [Line Items]
Topic 606 revenue	33	33	67	64
All other revenue	0	0	0	0
Foreign exchange trading services	33	33	67	64
Operating Segments | Investment Management | Securities finance
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	4	0	5	0
Securities finance	4	0	5	0
Operating Segments | Investment Management | Processing fees and other
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	5	2	16	1
Processing fees and other	5	2	16	1
Operating Segments | Investment Management | Total fee revenue
Disaggregation of Revenue [Line Items]
Topic 606 revenue	474	498	928	1,001
All other revenue	9	2	21	1
Total fee revenue	483	500	949	1,002
Operating Segments | Investment Management | Net interest income
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	(10)	(4)	(16)	(9)
Net interest income	(10)	(4)	(16)	(9)
Operating Segments | Investment Management | Gains (losses) related to investment securities, net
Disaggregation of Revenue [Line Items]
Topic 606 revenue	0	0	0	0
All other revenue	0	0	0	0
Gains (losses) related to investment securities, net	0	0	0	0
Other
Disaggregation of Revenue [Line Items]
Servicing fees	0	0	0	0
Management fees	0	0	0	0
Foreign exchange trading services	0	0	0	0
Securities finance	0	0	0	0
Processing fees and other	0	0	0	0
Total fee revenue	0	0	0	0
Net interest income	0	0	0	0
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	$ 0	$ 0	$ 0	$ 0