Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2023	Dec. 31, 2022
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (12)	$ (19)
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,528	$ 1,523
Derivative Average Remaining Maturity	[1],[3]	9 years	9 years 4 months 24 days
Standard Poors AAA To A Minus Ratings [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (13)	$ (18)
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 428	$ 428
Derivative Average Remaining Maturity	[1],[3]	18 years 6 months	18 years 8 months 12 days
Standard Poors BBB Rating [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ 2	$ 1
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 160	$ 155
Derivative Average Remaining Maturity	[1],[3]	3 years	3 years 3 months 18 days
Standard Poors BBB Rating [Member] | Credit Default Swaps Referencing Indices [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ 0	$ 0
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 915	$ 915
Derivative Average Remaining Maturity	[1],[3]	5 years 9 months 18 days	6 years 2 months 12 days
Standard Poors BBB Rating [Member] | Credit Default Subtotal [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ 2	$ 1
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,075	$ 1,070
Derivative Average Remaining Maturity	[1],[3]	5 years 4 months 24 days	5 years 9 months 18 days
Standard & Poor's, BB Rating [Member]
Credit Derivatives [Line Items]
Derivative Average Remaining Maturity	[1],[2]	2 years 10 months 24 days	3 years 2 months 12 days
Standard & Poor's, BB Rating [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (1)	$ (2)
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 25	$ 25

[1] The rating agency designations are based on ratings from Standard and Poor’s (“S&P”).

[2] Assumes the value of the referenced credit obligations is zero.

[3] The weighted average years to maturity of the credit default swaps is calculated based on weighted average notional amounts.