Investments (Investment Income Realized Investment Gains And Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment income:
Interest	$ 455	$ 446	$ 445
Dividends	220	201	181
Other	8	12	5
Total	683	659	631
Less investment expenses	13	13	12
Total	670	646	619
Gain (Loss) on Sale of Investments	851	1,640	(408)
Investment gains and losses, net:
Other	10	(3)	(12)
Total	865	1,650	(402)
Fixed Maturities
Investment gains and losses, net:
Gross realized gains	16	13	12
Gross realized losses	(3)	(3)	(2)
Write-down of impaired securities	(78)	(9)	(5)
Total	(65)	1	5
Equity Securities
Investment income:
Gain (Loss) on Sale of Investments	79	26	9
Unrealized Gain (Loss) on Investments	841	1,626	(404)
Investment gains and losses, net:
Total	$ 920	$ 1,652	$ (395)