Fair Value - Financial Assets and Liabilities Not Measured at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Carrying Amount
Assets:
Other invested assets, primarily mortgage loans	$ 1,006	$ 1,040
Liabilities:
Short term debt	907	853
Long term debt	8,146	8,160
Estimated Fair Value
Assets:
Other invested assets, primarily mortgage loans	958	973
Liabilities:
Short term debt	908	855
Long term debt	7,735	7,621
Estimated Fair Value | Level 1
Assets:
Other invested assets, primarily mortgage loans
Liabilities:
Short term debt
Long term debt
Estimated Fair Value | Level 2
Assets:
Other invested assets, primarily mortgage loans
Liabilities:
Short term debt	742	744
Long term debt	7,167	7,035
Estimated Fair Value | Level 3
Assets:
Other invested assets, primarily mortgage loans	958	973
Liabilities:
Short term debt	166	111
Long term debt	$ 568	$ 586