Summary of Significant Accounting Policies - Effects of Adoption of ASU 2018-12, Stockholders' Equity (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity	$ 16,525	$ 15,201	$ 17,471	$ 16,835
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity		15,478		19,181
Accumulated Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity	(2,497)	(3,320)	(1,320)	(1,516)
Accumulated Other Comprehensive Income (Loss) | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				581
Accumulated Other Comprehensive Income (Loss) | De-recognition of shadow reserves
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				2,331
Accumulated Other Comprehensive Income (Loss) | Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				(4,428)
Accumulated Other Comprehensive Income (Loss) | Other adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity	15,617	14,931	14,754	14,145
Retained Earnings | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				14,150
Retained Earnings | De-recognition of shadow reserves
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity
Retained Earnings | Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity
Retained Earnings | Other adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				(5)
Noncontrolling Interests
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity	$ 821	$ 852	$ 1,153	1,077
Noncontrolling Interests | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				1,321
Noncontrolling Interests | De-recognition of shadow reserves
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				270
Noncontrolling Interests | Re-measurement of LFPB using an upper-medium grade fixed income instrument yield discount rate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				(513)
Noncontrolling Interests | Other adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total equity				$ (1)