Reinsurance - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance recoverable credit loss	$ 33	$ 1	$ 34	$ 6
Reinsurance loss on uncollectible accounts in period amount	69	$ 0	69	$ 0
Scottish Re Group Limited
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance recoverable credit loss	33
Reinsurance recoverable allowance for credit loss	36		36
Reinsurance loss on uncollectible accounts in period amount			$ 69
Ceded, written	$ 33