Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reinsurance Retention Policy [Line Items]
Beginning balance	$ 5,442	$ 4,738	$ 3,776
Acquisition			324
Acquisition costs deferred	7,776	7,338	6,874
Amortization charged to income	(7,246)	(6,604)	(6,205)
Experience adjustment	(32)	(30)	(31)
Ending balance	5,940	5,442	4,738
Accident and health
Reinsurance Retention Policy [Line Items]
Beginning balance	322	339	333
Acquisition			3
Acquisition costs deferred	100	88	93
Amortization charged to income	(73)	(77)	(64)
Experience adjustment	(28)	(28)	(26)
Ending balance	321	322	339
Traditional life
Reinsurance Retention Policy [Line Items]
Beginning balance	79	47	32
Acquisition			0
Acquisition costs deferred	33	40	26
Amortization charged to income	(21)	(7)	(10)
Experience adjustment	(1)	(1)	(1)
Ending balance	90	79	47
Interest-sensitive life
Reinsurance Retention Policy [Line Items]
Beginning balance	101	90	97
Acquisition			0
Acquisition costs deferred	16	27	14
Amortization charged to income	(14)	(15)	(17)
Experience adjustment	(3)	(1)	(4)
Ending balance	100	101	90
Accident and health insurance short-duration contracts
Reinsurance Retention Policy [Line Items]
Beginning balance	26	17	10
Acquisition			0
Acquisition costs deferred	13	16	13
Amortization charged to income	(10)	(7)	(6)
Experience adjustment	0	0	0
Ending balance	29	26	17
Property and casualty
Reinsurance Retention Policy [Line Items]
Beginning balance	4,914	4,245	3,304
Acquisition			321
Acquisition costs deferred	7,614	7,167	6,728
Amortization charged to income	(7,128)	(6,498)	(6,108)
Experience adjustment	0	0	0
Ending balance	$ 5,400	$ 4,914	$ 4,245