Loans, Lending Commitments and Related Allowance for Credit Losses - Allowance for Credit Losses Rollforward - Loans and Lending Commitments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Allowance for loan losses rollforward
Beginning balance		$ 1,169	$ 839
Gross charge-offs		(155)	(141)
Recoveries		7	1
Net (charge-offs) recoveries		(148)	(140)
Provision (release)	$ 123	81	462
Other		2	(4)
Ending balance	$ 1,157	$ 1,104	$ 1,157
Percent of loans to total loans	100.00%	100.00%	100.00%
Allowance for lending commitments rollforward
Beginning balance		$ 551	$ 504
Provision (release)	$ 11	68	67
Other		0	(2)
Ending balance	569	619	569
Total ending balance	1,726	1,723	1,726
Corporate
Allowance for loan losses rollforward
Beginning balance		241	235
Gross charge-offs		(39)	(30)
Recoveries		0	0
Net (charge-offs) recoveries		(39)	(30)
Provision (release)		24	44
Other		1	(1)
Ending balance	$ 248	$ 227	$ 248
Percent of loans to total loans	4.00%	3.00%	4.00%
Allowance for lending commitments rollforward
Beginning balance		$ 431	$ 411
Provision (release)		41	29
Other		(1)	(1)
Ending balance	$ 439	471	439
Total ending balance	687	698	687
Secured lending facilities
Allowance for loan losses rollforward
Beginning balance		153	153
Gross charge-offs		(11)	0
Recoveries		0	0
Net (charge-offs) recoveries		(11)	0
Provision (release)		(12)	2
Other		0	(1)
Ending balance	$ 154	$ 130	$ 154
Percent of loans to total loans	19.00%	21.00%	19.00%
Allowance for lending commitments rollforward
Beginning balance		$ 70	$ 51
Provision (release)		19	24
Other		1	0
Ending balance	$ 75	90	75
Total ending balance	229	220	229
Commercial real estate
Allowance for loan losses rollforward
Beginning balance		463	275
Gross charge-offs		(103)	(108)
Recoveries		4	0
Net (charge-offs) recoveries		(99)	(108)
Provision (release)		44	261
Other		3	(2)
Ending balance	$ 426	$ 411	$ 426
Percent of loans to total loans	4.00%	4.00%	4.00%
Allowance for lending commitments rollforward
Beginning balance		$ 26	$ 15
Provision (release)		9	12
Other		0	(1)
Ending balance	$ 26	35	26
Total ending balance	452	446	452
Residential real estate
Allowance for loan losses rollforward
Beginning balance		100	87
Gross charge-offs		0	0
Recoveries		0	1
Net (charge-offs) recoveries		0	1
Provision (release)		(10)	22
Other		0	0
Ending balance	$ 110	$ 90	$ 110
Percent of loans to total loans	28.00%	30.00%	28.00%
Allowance for lending commitments rollforward
Beginning balance		$ 4	$ 4
Provision (release)		0	0
Other		0	0
Ending balance	$ 4	4	4
Total ending balance	114	94	114
SBL and Other
Allowance for loan losses rollforward
Beginning balance		212	89
Gross charge-offs		(2)	(3)
Recoveries		3	0
Net (charge-offs) recoveries		1	(3)
Provision (release)		35	133
Other		(2)	0
Ending balance	$ 219	$ 246	$ 219
Percent of loans to total loans	45.00%	42.00%	45.00%
Allowance for lending commitments rollforward
Beginning balance		$ 20	$ 23
Provision (release)		(1)	2
Other		0	0
Ending balance	$ 25	19	25
Total ending balance	$ 244	$ 265	$ 244