Segment Information - Schedule of Reportable Operating Segments, Consolidated Revenue and Segment Operating Income (Details) $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)
Revenue
Total revenue	$ 5,034	$ 4,729
Expenses
Compensation and benefits	2,393	2,249
Information technology	144	136
Premises	81	82
Other expenses	701	801
Total operating expenses	3,319	3,268
Operating income	$ 1,715	$ 1,461
Operating margin	0.341	0.309
Interest income	$ 12	$ 5
Interest expense	(179)	(206)
Other income (expense)	5	(10)
Income before income taxes	1,553	1,250
Risk Capital
Expenses
Investment income	53	65
Human Capital
Expenses
Investment income	2	2
Operating Segments | Risk Capital
Revenue
Total revenue	3,502	3,191
Expenses
Compensation and benefits	1,632	1,461
Information technology	96	90
Premises	53	52
Other expenses	339	391
Total operating expenses	2,120	1,994
Operating income	$ 1,382	$ 1,197
Operating margin	0.395	0.375
Operating Segments | Human Capital
Revenue
Total revenue	$ 1,539	$ 1,545
Expenses
Compensation and benefits	759	774
Information technology	46	45
Premises	27	29
Other expenses	264	294
Total operating expenses	1,096	1,142
Operating income	$ 443	$ 403
Operating margin	0.288	0.261
Corporate/Eliminations
Revenue
Total revenue	$ (7)	$ (7)
Expenses
Compensation and benefits	2	14
Information technology	2	1
Premises	1	1
Other expenses	98	116
Total operating expenses	103	132
Operating income	$ (110)	$ (139)