Derivative Financial Instruments and Off-balance Sheet Financial Instruments - Schedule of OTC Derivatives Counterparty Credit Exposure by Counterparty Credit Rating (Details) $ in Millions	Dec. 31, 2024 USD ($) counter-party	Dec. 31, 2023 USD ($) counter-party
Credit Derivatives
Number of counter-parties | counter-party	4	0
Notional amount	$ 602	$ 0
Credit exposure	20	0
Exposure, net of collateral	$ 2	$ 0
AA-
Credit Derivatives
Number of counter-parties | counter-party	1	0
Notional amount	$ 213	$ 0
Credit exposure	10	0
Exposure, net of collateral	$ 1	$ 0
A+
Credit Derivatives
Number of counter-parties | counter-party	3	0
Notional amount	$ 389	$ 0
Credit exposure	10	0
Exposure, net of collateral	$ 1	$ 0