Future Policy Benefit Reserves - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Insurance [Abstract]
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact	$ 1,000,000	$ 5,000,000
Liability for future policy benefit, gross premium income	115,000,000	120,000,000
Liability for future policy benefit, expected future gross premium, discounted, before reinsurance	$ 4,046,000,000	$ 4,567,000,000
Liability for future policy benefit, weighted-average duration	12 years	12 years
Liability for future policy benefit, adverse development, expense	$ 13,000,000	$ 0
Liability future policy benefit, losses recognized in prior period	$ 11,000,000	$ 1,000,000