Summary of Significant Accounting Policies - Effect of Adoption, Reserves For Future Policy Benefits and Claims Payable (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				$ 14,022
Reserves for future policy benefits and claims payable at January 1, 2021				16,796
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				12,285
Other future policy benefits and claims payable				2,774
Reserves for future policy benefits and claims payable at January 1, 2021				16,796	$ 22,512
Adjustment for loss contracts under the modified retrospective approach
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				37
Effect of remeasurement of liability at current discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				1,700
Revision of Prior Period, Accounting Standards Update, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021				(5,716)
Payout Annuity
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				1,295
Effect of changes in cash flow assumptions		$ 0	$ 4
Reserves for future policy benefits and claims payable at January 1, 2021	$ 996	971
Payout Annuity | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				1,148
Payout Annuity | Adjustment for loss contracts under the modified retrospective approach
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				4
Payout Annuity | Effect of remeasurement of liability at current discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				143
Closed Block Life
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				6,384
Effect of changes in cash flow assumptions		65	331
Reserves for future policy benefits and claims payable at January 1, 2021	1,794	1,898
Closed Block Life | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				5,809
Closed Block Life | Adjustment for loss contracts under the modified retrospective approach
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				15
Closed Block Life | Effect of remeasurement of liability at current discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				560
Closed Block Annuity
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				6,343
Effect of changes in cash flow assumptions		(3)	$ (15)
Reserves for future policy benefits and claims payable at January 1, 2021	$ 4,211	$ 4,432
Closed Block Annuity | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits				5,328
Closed Block Annuity | Adjustment for loss contracts under the modified retrospective approach
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				18
Closed Block Annuity | Effect of remeasurement of liability at current discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of changes in cash flow assumptions				997
Reserve For Future Policy Benefits
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021				14,022
Reserve For Future Policy Benefits | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021					12,285
Reserve For Future Policy Benefits | Revision of Prior Period, Accounting Standards Update, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021				1,737
Other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021				2,774
Other | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021					$ 10,227
Other | Revision of Prior Period, Accounting Standards Update, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reserves for future policy benefits and claims payable at January 1, 2021				$ (7,453)