Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
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)
Total revenue	3,065	2,932
Provision for credit losses	36	4
Total expenses	2,255	2,293
Income before income tax expense	$ 774	$ 635
Pre-tax margin	25.00%	22.00%
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
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)
Total revenue	2,612	2,472
Provision for credit losses	36	4
Total expenses	1,859	1,864
Income before income tax expense	$ 717	$ 604
Pre-tax margin	27.00%	24.00%
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
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
Total revenue	453	460
Provision for credit losses	0	0
Total expenses	385	406
Income before income tax expense	$ 68	$ 54
Pre-tax margin	15.00%	12.00%
Other
Segment Reporting Information [Line Items]
Servicing fees	$ 0	$ 0
Management fees	0	0
Foreign exchange trading services	0	0
Securities finance	0	0
Software and processing fees	0	0
Total fee revenue	0	0
Net interest income	0	0
Total fee revenue	0	0
Total revenue	0	0
Provision for credit losses	0	0
Total expenses	11	23
Income before income tax expense	$ (11)	$ (23)