Derivatives (Credit Derivatives) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Estimated Fair Value of Credit Default Swaps	$ 38	$ 41
Maximum Amount of Future Payments under Credit Default Swaps	$ 1,724	$ 1,755
Weighted Average Years to Maturity (2)	4 years 1 month 6 days	4 years 3 months 18 days
Credit default swaps | Aaa/Aa/A
Derivative [Line Items]
Estimated Fair Value of Credit Default Swaps	$ 12	$ 15
Maximum Amount of Future Payments under Credit Default Swaps	$ 589	$ 683
Weighted Average Years to Maturity (2)	2 years 4 months 24 days	2 years 10 months 24 days
Credit default swaps | Baa
Derivative [Line Items]
Estimated Fair Value of Credit Default Swaps	$ 27	$ 26
Maximum Amount of Future Payments under Credit Default Swaps	$ 1,131	$ 1,072
Weighted Average Years to Maturity (2)	5 years	5 years 2 months 12 days
Credit default swaps | Caa and Lower
Derivative [Line Items]
Estimated Fair Value of Credit Default Swaps	$ (1)	$ 0
Maximum Amount of Future Payments under Credit Default Swaps	$ 4	$ 0
Weighted Average Years to Maturity (2)	4 years	0 years