Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Servicing fees	$ 1,275	$ 1,228
Management fees	562	510
Foreign exchange trading services	362	331
Securities finance	114	96
Software and processing fees	225	207
Other fee revenue	32	50
Total fee revenue	2,570	2,422
Net interest income	714	716
Total revenue	3,284	3,138
Provision for credit losses	12	27
Compensation and employee benefits expenses	1,262	1,252
Information systems and communications	497	432
Transaction processing services	258	248
Other	433	581
Total expenses	2,450	2,513
Income before income tax expense	$ 822	$ 598
Pre-tax margin	25.00%	19.00%
Average assets (in billions)	$ 337,300	$ 298,600
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees	1,275	1,228
Management fees	0	0
Foreign exchange trading services	337	308
Securities finance	108	90
Software and processing fees	225	207
Other fee revenue	34	43
Total fee revenue	1,979	1,876
Net interest income	709	711
Total revenue	2,688	2,587
Provision for credit losses	12	27
Compensation and employee benefits expenses	1,103	1,099
Information systems and communications	477	417
Transaction processing services	216	206
Other	223	241
Total expenses	2,019	1,963
Income before income tax expense	$ 657	$ 597
Pre-tax margin	24.00%	23.00%
Average assets (in billions)	$ 333,900	$ 295,500
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
Servicing fees	0	0
Management fees	562	510
Foreign exchange trading services	25	23
Securities finance	6	6
Software and processing fees	0	0
Other fee revenue	(2)	7
Total fee revenue	591	546
Net interest income	5	5
Total revenue	596	551
Provision for credit losses	0	0
Compensation and employee benefits expenses	159	153
Information systems and communications	20	15
Transaction processing services	42	42
Other	210	210
Total expenses	431	420
Income before income tax expense	$ 165	$ 131
Pre-tax margin	28.00%	24.00%
Average assets (in billions)	$ 3,400	$ 3,100
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
Other fee revenue	0	0
Total fee revenue	0	0
Net interest income	0	0
Total revenue	0	0
Provision for credit losses	0	0
Compensation and employee benefits expenses	0	0
Information systems and communications	0	0
Transaction processing services	0	0
Other	0	130
Total expenses	0	130
Income before income tax expense	$ 0	$ (130)