Investments (Investment Income Net of Related Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	$ 890	$ 837
Investment expense	(34)	(27)
Investment income, net of related expenses	856	810
Available-for-sale Securities [Member]
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	645	533
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	74	73
Policy loans
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	13	13
Funds withheld at interest
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	72	51
Short-term Investments [Member]
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	21	2
Partnership Interest
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	54	161
Other invested assets
Major Categories Of Investment Income Net of Expenses [Line Items]
Investment revenue	$ 9	$ 2