Business, Basis of Presentation and Significant Accounting Policies - Adoption of New Pronouncements (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ 5,683,000,000	$ 6,213,000,000	$ 9,821,000,000	$ 9,995,000,000	$ 9,775,000,000	$ 11,178,000,000
Accumulated other comprehensive income (loss)			(1,986,000,000)		2,100,000,000	2,316,000,000
Forecast
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	Accounting Standards Update 2018-12 [Member]
Cumulative Effect, Period of Adoption, Adjustment, Other Adjustment Balances | Forecast | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		$ 100,000,000
Liability for Future Policy Benefits, Period Increase (Decrease)		1,300,000,000
Cumulative Effect, Period of Adoption, Adjustment, Other Adjustment Balances | Forecast | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		200,000,000
Retained Earnings (Accumulated Deficit)		(100,000,000)
Accumulated other comprehensive income (loss)		$ (1,000,000,000)
Accumulated Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ (1,986,000,000)	$ (963,000,000)	$ 2,100,000,000	$ 2,316,000,000	$ 2,431,000,000	$ 4,898,000,000