Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Servicing fees	$ 1,395	$ 1,301	$ 4,165	$ 3,860
Management fees	526	479	1,523	1,387
Foreign exchange trading services	279	270	911	1,039
Securities finance	106	84	314	268
Software and processing fees	198	172	588	529
Total fee revenue	2,504	2,306	7,501	7,083
Net interest income	487	478	1,421	1,701
Total other income (loss)	(1)	0	52	2
Total revenue	2,990	2,784	8,974	8,786
Provision for credit losses	(2)	0	(26)	88
Total expenses	2,116	2,103	6,559	6,440
Income before income tax expense	$ 876	$ 681	$ 2,441	$ 2,258
Pre-tax margin	29.00%	24.00%	27.00%	26.00%
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees	$ 1,395	$ 1,301	$ 4,165	$ 3,860
Management fees	0	0	0	0
Foreign exchange trading services	266	252	869	998
Securities finance	103	81	304	258
Software and processing fees	204	162	585	528
Total fee revenue	1,968	1,796	5,923	5,644
Net interest income	491	482	1,432	1,716
Total other income (loss)	(1)	0	(1)	2
Total revenue	2,458	2,278	7,354	7,362
Provision for credit losses	(2)	0	(26)	88
Total expenses	1,755	1,739	5,389	5,315
Income before income tax expense	$ 705	$ 539	$ 1,991	$ 1,959
Pre-tax margin	29.00%	24.00%	27.00%	27.00%
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
Servicing fees	$ 0	$ 0	$ 0	$ 0
Management fees	526	479	1,523	1,387
Foreign exchange trading services	13	18	42	41
Securities finance	3	3	10	10
Software and processing fees	(6)	10	3	1
Total fee revenue	536	510	1,578	1,439
Net interest income	(4)	(4)	(11)	(15)
Total other income (loss)	0	0	0	0
Total revenue	532	506	1,567	1,424
Provision for credit losses	0	0	0	0
Total expenses	339	358	1,082	1,096
Income before income tax expense	$ 193	$ 148	$ 485	$ 328
Pre-tax margin	36.00%	29.00%	31.00%	23.00%
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 (loss)	0	0	53	0
Total revenue	0	0	53	0
Provision for credit losses	0	0	0	0
Total expenses	22	6	88	29
Income before income tax expense	$ (22)	$ (6)	$ (35)	$ (29)