Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Servicing fees		$ 5,324	$ 5,016	$ 4,922
Management fees		2,398	2,124	1,876
Foreign exchange trading services		1,614	1,401	1,265
Securities finance		505	438	426
Software and processing fees		903	888	811
Other fee revenue		236	289	180
Total fee revenue		10,980	10,156	9,480
Net interest income		2,960	2,923	2,759
Total other income		4	(79)	(294)
Total revenue		13,944	13,000	11,945
Provision for credit losses	$ 59	59	75	46
Compensation and employee benefits expenses		5,035	4,697	4,744
Information systems and communications		2,094	1,829	1,703
Transaction processing services		1,050	998	957
Other		1,975	2,006	2,179
Total expenses		10,154	9,530	9,583
Income before income tax expense		$ 3,731	$ 3,395	$ 2,316
Pre-Tax Margin		27.00%	26.00%	19.00%
Average assets (in billions)		$ 343,500	$ 311,700	$ 274,700
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees		5,324	5,016	4,922
Management fees		0	0	0
Foreign exchange trading services		1,441	1,248	1,140
Securities finance		481	415	402
Software and processing fees		927	888	811
Other fee revenue		209	188	145
Total fee revenue		8,382	7,755	7,420
Net interest income		2,945	2,899	2,740
Total other income		4	2	0
Total revenue		11,331	10,656	10,160
Provision for credit losses		59	75	46
Compensation and employee benefits expenses		4,220	4,078	4,033
Information systems and communications		1,960	1,743	1,568
Transaction processing services		875	825	777
Other		1,001	1,041	1,035
Total expenses		8,056	7,687	7,413
Income before income tax expense		$ 3,216	$ 2,894	$ 2,701
Pre-Tax Margin		28.00%	27.00%	27.00%
Average assets (in billions)		$ 339,900	$ 308,500	$ 271,500
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
Servicing fees		0	0	0
Management fees		2,398	2,124	1,876
Foreign exchange trading services		170	138	125
Securities finance		24	23	24
Software and processing fees		0	0	0
Other fee revenue		27	35	35
Total fee revenue		2,619	2,320	2,060
Net interest income		15	24	19
Total other income		0	0	0
Total revenue		2,634	2,344	2,079
Provision for credit losses		0	0	0
Compensation and employee benefits expenses		604	555	520
Information systems and communications		92	86	94
Transaction processing services		175	173	180
Other		904	841	746
Total expenses		1,775	1,655	1,540
Income before income tax expense		$ 859	$ 689	$ 539
Pre-Tax Margin		33.00%	29.00%	26.00%
Average assets (in billions)		$ 3,600	$ 3,200	$ 3,200
Other
Segment Reporting Information [Line Items]
Servicing fees		0	0	0
Management fees		0	0	0
Foreign exchange trading services		3	15	0
Securities finance		0	0	0
Software and processing fees		(24)	0	0
Other fee revenue		0	66	0
Total fee revenue		(21)	81	0
Net interest income		0	0	0
Total other income		0	(81)	(294)
Total revenue		(21)	0	(294)
Provision for credit losses		0	0	0
Compensation and employee benefits expenses		211	64	191
Information systems and communications		42	0	41
Transaction processing services		0	0	0
Other		70	124	398
Total expenses		323	188	630
Income before income tax expense		$ (344)	$ (188)	$ (924)