Investments (Investment Income Net of Related Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	$ 1,284	$ 1,000
Investment expense	(52)	(39)
Investment income, net of related expenses	1,232	961
Available-for-sale Securities [Member]
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	1,063	760
Equity securities
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	2	2
Mortgage Loans on Real Estate [Member]
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	119	90
Policy loans
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	18	14
Funds withheld at interest
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	66	89
Short-term Investments [Member]
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	36	34
Partnership Interest
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	(15)	7
Other invested assets
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	$ (5)	$ 4