Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 28	$ 13
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,321	$ 1,517
Derivative Average Remaining Maturity	[1],[3]	9 years	5 years 7 months 6 days
Standard Poors AAA To A Ratings [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 28	$ 11
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 600	$ 287
Derivative Average Remaining Maturity	[1],[3]	14 years 2 months 12 days	15 years
Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 1	$ 2
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 706	$ 1,220
Derivative Average Remaining Maturity	[1],[3]	4 years 7 months 6 days	3 years 6 months
Standard & Poor's, BB+ Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ (1)	$ 0
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 15	$ 10
Derivative Average Remaining Maturity	[1],[3]	3 years 6 months	8 months 12 days
Single Name Credit Default Swaps [Member] | Standard Poors AAA To A Ratings [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 28	$ 11
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 600	$ 287
Derivative Average Remaining Maturity	[1],[3]	14 years 2 months 12 days	15 years
Single Name Credit Default Swaps [Member] | Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 1	$ 2
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 141	$ 232
Derivative Average Remaining Maturity	[1],[3]	2 years 4 months 24 days	1 year 7 months 6 days
Single Name Credit Default Swaps [Member] | Standard & Poor's, BB+ Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ (1)	$ 0
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 15	$ 10
Derivative Average Remaining Maturity	[1],[3]	3 years 6 months	8 months 12 days
Credit Default Swaps Referencing Indices [Member] | Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 0	$ 0
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 565	$ 988
Derivative Average Remaining Maturity	[1],[3]	5 years 1 month 6 days	3 years 10 months 24 days

[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