Future Policy Benefits Reserves - Summary of Balances and Changes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Present value of future net premiums
Balance, January 1			$ 3,993	$ 4,735
Effect of changes in discount rate	$ 154	$ 525	(74)	(880)
Balance, January 1, at original locked in discount rate			3,919	3,855
Effect of changes in cash flow assumptions
Expect of actual variances from expected experience			(49)	(18)
Adjusted balance, January 1	3,811	3,778	3,870	3,837
Interest accrual	52	53
Net premiums: earned during period	(111)	(112)
Balance, end of period at original locked in discount rate	3,811	3,778
Effect of changes in discount rate	154	525	(74)	(880)
Balance, March 31	3,965	4,303
Present value of future benefits & expenses
Balance, January 1			17,472	22,745
Effect of changes in discount rate	704	3,517	(125)	(5,942)
Balance, January 1, at original locked in discount rate	17,347	16,803
Effect of changes in cash flow assumptions
Effect of actual variances from expected experience			(50)	(23)
Adjusted balance, January 1			17,297	16,780
Interest accrual	242	241
Benefit & expense payments	(302)	(233)
Balance, end of period at original locked in discount rate	17,237	16,788
Effect of changes in discount rate	704	3,517	(125)	$ (5,942)
Balance, March 31	17,941	20,305
Net LFPB	13,976	16,002	$ 13,480		$ 19,132
Re-measurement gain of insurance claims and policyholders’ benefits	$ 1	$ 5