Reserve for Property and Casualty Insurance Claims and Claims Expense - Rollforward of the reserve for property and casualty insurance claims and claims expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Incurred claims and claims expense related to:
Prior years	$ 459	$ 15	$ 604	$ (226)
National General
Activity in the reserve for property-liability insurance claims and claims expense:
National General acquisition as of January 4, 2021			0	1,797
Property-Liability
Activity in the reserve for property-liability insurance claims and claims expense:
Beginning balance			33,060	27,610
Less recoverables			(9,479)	(7,033)
Net balance as of January 1			23,581	20,577
Incurred claims and claims expense related to:
Current year			16,585	13,476
Prior years			604	(226)
Total incurred			17,189	13,250
Claims and claims expense paid related to:
Current year			(7,753)	(6,919)
Prior years			(7,691)	(6,134)
Total paid			(15,444)	(13,053)
Net balance as of June 30	25,326	22,571	25,326	22,571
Plus recoverables	8,950	9,066	8,950	9,066
Ending balance	$ 34,276	$ 31,637	$ 34,276	$ 31,637