Long-term and Short-term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt instrument, carrying value	$ 833	$ 836
Surplus Note Due 2059
Debt Instrument [Line Items]
Debt instrument, stated interest rate	8.07%	8.07%
Debt instrument, carrying value	$ 412	$ 412
Surplus Note Due Dec 2058
Debt Instrument [Line Items]
Debt instrument, stated interest rate	8.15%	8.15%
Debt instrument, carrying value	$ 200	$ 200
Surplus Note Due Sep 2058
Debt Instrument [Line Items]
Debt instrument, stated interest rate	7.80%	7.80%
Debt instrument, carrying value	$ 200	$ 200
Non-recourse Debt Due 2030
Debt Instrument [Line Items]
Debt instrument, stated interest rate	7.028%	7.028%
Debt instrument, carrying value	$ 21	$ 24