Claim and Claim Adjustment Expense Reserves and Future Policy Benefit Reserves - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Loss from catastrophes, net of reinsurance	$ 114	$ 178	$ 171	$ 357
Decrease in provision for insured events of prior years			(144)	(130)
Commercial Property and Casualty Operations
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Decrease in provision for insured events of prior years	(17)	(10)	(66)	(36)
Other insurance operations
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Decrease in provision for insured events of prior years			64	$ 40
Hurricane
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Catastrophe losses, net of reinsurance	$ 87	$ 114	$ 87