Segment Information - Schedule of Reportable Operating Segments, Consolidated Revenue and Segment Operating Income (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)
Revenue
Total revenue	$ 4,155	$ 3,760	$ 8,884	$ 7,830
Expenses
Compensation and benefits	2,360	2,130	4,609	4,013
Information technology	136	132	272	256
Premises	85	82	167	153
Other Expenses	715	760	1,516	1,287
Total operating expenses	3,296	3,104	6,564	5,709
Operating income	$ 859	$ 656	$ 2,320	$ 2,121
Operating margin	0.207	0.174	0.261	0.271
Interest income	$ 0	$ 31	$ 5	$ 59
Interest expense	(212)	(225)	(418)	(369)
Other income (expense)	56	236	46	311
Income before income taxes	703	698	1,953	2,122
Risk Capital
Expenses
Investment income	60	73	125	151
Human Capital
Expenses
Investment income	1	2	2	3
Operating Segments | Risk Capital
Revenue
Total revenue	2,866	2,650	6,057	5,625
Expenses
Compensation and benefits	1,541	1,390	3,002	2,744
Information technology	88	93	178	182
Premises	54	54	106	104
Other Expenses	319	329	710	626
Total operating expenses	2,002	1,866	3,996	3,656
Operating income	$ 864	$ 784	$ 2,061	$ 1,969
Operating margin	0.301	0.296	0.340	0.350
Operating Segments | Human Capital
Revenue
Total revenue	$ 1,291	$ 1,125	$ 2,836	$ 2,228
Expenses
Compensation and benefits	796	710	1,570	1,237
Information technology	45	39	90	74
Premises	30	28	59	49
Other Expenses	303	258	597	391
Total operating expenses	1,174	1,035	2,316	1,751
Operating income	$ 117	$ 90	$ 520	$ 477
Operating margin	0.091	0.080	0.183	0.214
Corporate/Eliminations
Revenue
Total revenue	$ (2)	$ (15)	$ (9)	$ (23)
Expenses
Compensation and benefits	23	30	37	32
Information technology	3	0	4	0
Premises	1	0	2	0
Other Expenses	93	173	209	270
Total operating expenses	120	203	252	302
Operating income	$ (122)	$ (218)	$ (261)	$ (325)