Derivative Financial Instruments and Off-balance Sheet Financial Instruments - Schedule of Volume and Fair Value Positions of Derivative Instruments (Details) - Derivatives not designated as accounting hedging instruments $ in Millions	Dec. 31, 2025 USD ($) contract	Dec. 31, 2024 USD ($) contract
Derivatives, Fair Value
Total asset derivatives, notional amount	$ 1,340	$ 852
Total liability derivatives, notional amount	82	0
Total derivatives, notional amount	$ 1,422	$ 852
Total asset derivatives, number of contracts \| contract	3,430	5,033
Total liability derivatives, number of contracts \| contract	2,398	12,774
Total derivatives, Number of contracts \| contract	5,828	17,807
Net amount on balance sheet	$ 142	$ 154
Net amount on balance sheet	(6)	(1)
Total derivatives, fair value, net	136	153
Asset derivatives, gross asset	158	155
Liability derivatives, gross asset	0	0
Asset derivatives, gross liability	(16)	(1)
Gross amount	(6)	$ (1)
Interest rate cap agreements
Derivatives, Fair Value
Total asset derivatives, notional amount	37
Net amount on balance sheet	0
Asset derivatives, gross asset	0
Asset derivatives, gross liability	$ 0
Futures
Derivatives, Fair Value
Total asset derivatives, number of contracts \| contract	3,386	4,596
Total liability derivatives, number of contracts \| contract	1,323	12,112
Net amount on balance sheet	$ 0	$ 0
Net amount on balance sheet	0	(1)
Asset derivatives, gross asset	0	0
Liability derivatives, gross asset	0	0
Asset derivatives, gross liability	0	0
Gross amount	$ 0	$ (1)
Options
Derivatives, Fair Value
Total asset derivatives, number of contracts \| contract	12
Total liability derivatives, number of contracts \| contract	12
Net amount on balance sheet	$ 0
Net amount on balance sheet	0
Asset derivatives, gross asset	0
Liability derivatives, gross asset	0
Asset derivatives, gross liability	0
Gross amount	$ 0
Futures
Derivatives, Fair Value
Total asset derivatives, number of contracts \| contract	32	437
Total liability derivatives, number of contracts \| contract	1,063	662
Net amount on balance sheet	$ 0	$ 0
Net amount on balance sheet	(2)	0
Asset derivatives, gross asset	0	0
Liability derivatives, gross asset	0	0
Asset derivatives, gross liability	0	0
Gross amount	(2)	0
Foreign currency forwards
Derivatives, Fair Value
Total asset derivatives, notional amount	503	602
Total liability derivatives, notional amount	45
Net amount on balance sheet	(14)	20
Net amount on balance sheet	(3)
Asset derivatives, gross asset	2	21
Liability derivatives, gross asset	0
Asset derivatives, gross liability	(16)	(1)
Gross amount	(3)
Contingent consideration
Derivatives, Fair Value
Total asset derivatives, notional amount	250	250
Net amount on balance sheet	147	134
Asset derivatives, gross asset	147	134
Asset derivatives, gross liability	0	$ 0
Credit default swaps – selling protection
Derivatives, Fair Value
Total asset derivatives, notional amount	550
Net amount on balance sheet	9
Asset derivatives, gross asset	9
Asset derivatives, gross liability	0
Interest rate swap agreements
Derivatives, Fair Value
Total liability derivatives, notional amount	37
Net amount on balance sheet	(1)
Liability derivatives, gross asset	0
Gross amount	$ (1)

Derivative Financial Instruments and Off-balance Sheet Financial Instruments - Schedule of Volume and Fair Value Positions of Derivative Instruments (Details) - Derivatives not designated as accounting hedging instruments
$ in Millions