Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($) $ in Millions		6 Months Ended		9 Months Ended
		Jun. 30, 2022		Sep. 30, 2021		Dec. 31, 2021
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (26)				$ 28
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,675				1,321
Derivative Average Remaining Maturity	[1],[3]	9 years 3 months 18 days		9 years
Standard Poors AAA To A Minus Ratings [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (23)				28
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 477				600
Derivative Average Remaining Maturity	[1],[3]	17 years 2 months 12 days		14 years 2 months 12 days
Standard Poors AAA To A Minus Ratings [Member] | Credit Default Subtotal [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (23)				28
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 477				600
Derivative Average Remaining Maturity	[1],[3]	17 years 2 months 12 days		14 years 2 months 12 days
Standard Poors BBB Rating [Member] | Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ 0				1
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 158				141
Derivative Average Remaining Maturity	[1],[3]	3 years 8 months 12 days		2 years 4 months 24 days
Standard Poors BBB Rating [Member] | Credit Default Swaps Referencing Indices [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (1)				0
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,015				565
Derivative Average Remaining Maturity	[1],[3]	6 years 7 months 6 days		5 years 1 month 6 days
Standard Poors BBB Rating [Member] | Credit Default Subtotal [Member]
Credit Derivatives [Line Items]
Credit Derivative Current Fair Value	[1]	$ (1)				1
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,173				706
Derivative Average Remaining Maturity	[1],[3]	6 years 2 months 12 days		4 years 7 months 6 days
Standard & Poor's, BB Rating [Member]
Credit Derivatives [Line Items]
Derivative Average Remaining Maturity	[1]	3 years 8 months 12 days	[3]	3 years 6 months	[2]
Standard & Poor's, BB 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]	25				15
Standard & Poor's, BB 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]	$ 25				$ 15

[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.