Derivatives - Credit Risk Assumed through Credit Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Credit Derivatives [Line Items]
Derivative, Notional Amount	$ 10,973	$ 11,224
Fair Value	(14)	(42)
Credit derivatives
Credit Derivatives [Line Items]
Derivative, Notional Amount	105	105
Fair Value	(2)	(2)
Offsetting Fair Value	2	2
Derivative, Nominal Value, Amount Offset Against Collateral, Net	105	105
Credit derivatives | Basket credit default swaps | Standard & Poor's, AAA Rating [Member] | Investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount	100	101
Fair Value	$ 0	$ 0
Weighted Average Years to Maturity	6 years	6 years
Offsetting Fair Value	$ 0	$ 0
Derivative, Nominal Value, Amount Offset Against Collateral, Net	100	101
Credit derivatives | Basket credit default swaps | Standard & Poor's, CCC Rating [Member] | Below investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount		4
Fair Value		$ (2)
Average Term of Credit Risk Derivatives Less than 1 Year		Less than 1 year
Offsetting Fair Value		$ 2
Derivative, Nominal Value, Amount Offset Against Collateral, Net		$ 4
Credit derivatives | Basket credit default swaps | Standard & Poor's, B- Rating | Below investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount	5
Fair Value	$ (2)
Average Term of Credit Risk Derivatives Less than 1 Year	Less than 1 year
Offsetting Fair Value	$ 2
Derivative, Nominal Value, Amount Offset Against Collateral, Net	$ 5