Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
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 other income	0	0	2	(1)
Total revenue	2,937	2,873	6,002	5,805
Provision for credit losses	52	1	88	5
Total expenses	2,082	2,154	4,337	4,447
Income before income tax expense	$ 803	$ 718	$ 1,577	$ 1,353
Pre-tax margin	27.00%	25.00%	26.00%	23.00%
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
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 other income			2	(1)
Total revenue	2,472	2,400	5,084	4,872
Provision for credit losses	52	1	88	5
Total expenses	1,717	1,765	3,576	3,629
Income before income tax expense	$ 703	$ 634	$ 1,420	$ 1,238
Pre-tax margin	28.00%	26.00%	28.00%	25.00%
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
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 other income			0	0
Total revenue	465	473	918	933
Provision for credit losses	0	0	0	0
Total expenses	353	377	738	783
Income before income tax expense	$ 112	$ 96	$ 180	$ 150
Pre-tax margin	24.00%	20.00%	20.00%	16.00%
Other
Segment Reporting Information [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
Software and processing fees	0	0	0	0
Total fee revenue	0	0	0	0
Net interest income	0	0	0	0
Total other income			0	0
Total revenue	0	0	0	0
Provision for credit losses	0	0	0	0
Total expenses	12	12	23	35
Income before income tax expense	$ (12)	$ (12)	$ (23)	$ (35)