Derivatives - Credit Risk Assumed through Credit Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Credit Derivatives [Line Items]
Derivative, Notional Amount	$ 12,923	$ 10,755
Fair Value	19	47
Derivative, Collateral, Right to Reclaim Cash	22	1
Securities Received as Collateral	1	1
Collateral Pledged
Credit Derivatives [Line Items]
Derivative, Collateral, Right to Reclaim Cash	16	16
Asset Pledged as Collateral [Member]
Credit Derivatives [Line Items]
Derivative, Collateral, Right to Reclaim Securities	8	8
Credit derivatives
Credit Derivatives [Line Items]
Derivative, Notional Amount	103	103
Fair Value	(4)	(3)
Derivative, Nominal Value, Amount Offset Against Collateral, Net	103	103
Offsetting Fair Value	4	3
Credit derivatives | Basket credit default swaps | Standard & Poor's, AAA Rating [Member] | Investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount	100	100
Fair Value	$ (2)	$ (1)
Weighted Average Years to Maturity	5 years	6 years
Derivative, Nominal Value, Amount Offset Against Collateral, Net	$ 100	$ 100
Offsetting Fair Value	2	1
Credit derivatives | Basket credit default swaps | Standard & Poor's, B- Rating | Below investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount		3
Fair Value		$ (2)
Average Term of Credit Risk Derivatives Less than 1 Year		Less than 1 year
Derivative, Nominal Value, Amount Offset Against Collateral, Net		$ 3
Offsetting Fair Value		$ 2
Credit derivatives | Basket credit default swaps | Standard & Poor's, CCC+ Rating | Below investment grade risk exposure
Credit Derivatives [Line Items]
Derivative, Notional Amount	3
Fair Value	$ (2)
Average Term of Credit Risk Derivatives Less than 1 Year	Less than 1 year
Derivative, Nominal Value, Amount Offset Against Collateral, Net	$ 3
Offsetting Fair Value	$ 2