Commitments and Contingencies - Pledged Assets and Funds in Trust (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Other Commitments [Line Items]
Investment funds	$ 18,846	$ 17,668
Derivative assets	7,529	5,298
Restricted cash	964
Total restricted assets	70,154	49,643
Asset Pledged as Collateral
Other Commitments [Line Items]
AFS securities	42,446	32,458
Debt Securities, Trading, Restricted	1,777	139
Equity securities	304	80
Mortgage loans, net of allowances	23,171	14,257
Investment funds	777	409
Derivative assets	68	73
Short-term Investments	14	153
Other investments	623	313
Restricted cash	$ 974	$ 1,761