Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Long Duration Contracts [Abstract]
Beginning balance	$ 502	$ 476
Acquisition costs deferred	109	122
Amortization charged to income	(82)	(73)
Experience adjustment	(25)	(28)
Total	504	497
Short-duration contracts	27	24
Property and casualty	5,293	4,770
Ending balance	5,824	5,291	$ 5,442
Accident and health insurance
Long Duration Contracts [Abstract]
Beginning balance	322	339
Acquisition costs deferred	73	66
Amortization charged to income	(54)	(55)
Experience adjustment	(22)	(26)
Total	319	324
Traditional life
Long Duration Contracts [Abstract]
Beginning balance	79	47
Acquisition costs deferred	24	33
Amortization charged to income	(17)	(7)
Experience adjustment	(1)	(1)
Total	85	72
Interest- sensitive life
Long Duration Contracts [Abstract]
Beginning balance	101	90
Acquisition costs deferred	12	23
Amortization charged to income	(11)	(11)
Experience adjustment	(2)	(1)
Total	$ 100	$ 101