Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets
Mortgage loans	$ 1,035	$ 1,040	[1]
Liabilities
Long-term debt	2,481	2,538	[1]
Carrying Amount
Assets
Mortgage loans	1,035	1,040
Liabilities
Short-term debt	550	243
Long-term debt	2,481	2,538
Estimated Fair Value
Assets
Mortgage loans	997	973
Liabilities
Short-term debt	546	248
Long-term debt	2,385	2,349
Level 1 | Estimated Fair Value
Assets
Mortgage loans	0	0
Liabilities
Short-term debt	0	0
Long-term debt	0	0
Level 2 | Estimated Fair Value
Assets
Mortgage loans	0	0
Liabilities
Short-term debt	546	248
Long-term debt	2,385	2,349
Level 3 | Estimated Fair Value
Assets
Mortgage loans	997	973
Liabilities
Short-term debt	0	0
Long-term debt	$ 0	$ 0

[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.