Fair Value - Financial Assets and Liabilities not Measured at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Carrying Amount
Assets:
Other invested assets, primarily mortgage loans	$ 1,055	$ 1,079
Liabilities:
Short-term debt	1	1,051
Long-term debt	8,933	8,435
Estimated Fair Value
Assets:
Other invested assets, primarily mortgage loans	1,043	1,072
Liabilities:
Short-term debt	1	1,053
Long-term debt	8,793	8,426
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		1,051
Long-term debt	7,801	7,431
Estimated Fair Value | Level 3
Assets:
Other invested assets, primarily mortgage loans	1,043	1,072
Liabilities:
Short-term debt	1	2
Long-term debt	$ 992	$ 995