Investments (Allowance For Credit Loss Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	$ 8	$ 51	$ 7	$ 0
Additions for securities for which no previous expected credit losses were recognized	0	10	1	61
Allowance for credit loss, securities sold	(2)	(8)	(2)	(8)
Increase (decrease) to the allowance for credit losses on securities	0	(29)	0	(29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	6	24	6	24
Corporate Securities [Member]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	6	51	7	0
Additions for securities for which no previous expected credit losses were recognized	0	9	1	60
Allowance for credit loss, securities sold	(2)	(8)	(2)	(8)
Increase (decrease) to the allowance for credit losses on securities	0	(29)	(2)	(29)
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	4	23	4	23
Residential Mortgage-Backed Securities [Member]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	2	0	0	0
Additions for securities for which no previous expected credit losses were recognized	0	1	0	1
Increase (decrease) to the allowance for credit losses on securities	0	0	2	0
Fixed Maturity Securities, Available-for-sale, Allowance for Credit Loss, Ending Balance	$ 2	$ 1	$ 2	$ 1