Long-Term Debt - Subordinated Debt (Details) - Parent Company - Subordinated Debt - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Nov. 20, 2013
Fixed Rate 8.25% Notes Due 2038
Debt Instrument
Issue of senior notes to third party investors	$ 1,000
Interest rate (as a percent)	8.25%
Amount of debt converted to floating rate	$ 705
Interest rate paid (as a percent)	8.66%
Fixed Rate 8.25% Notes Due 2038 | Secured Overnight Financing Rate (SOFR)
Debt Instrument
Basis spread on variable rate (as a percent)	3.31%
Fixed Rate 4.30% Notes Due 2024
Debt Instrument
Interest rate (as a percent)	4.30%	4.30%
Principal amount		$ 750