Investments (Investment Income Realized Investment Gains And Losses And Change In Unrealized Investment Gains And Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment income:
Interest	$ 440	$ 428	$ 417
Dividends	161	150	138
Other	3	3	2
Total	604	581	557
Less investment expenses	9	9	8
Total	595	572	549
Realized investment gains and losses:
Other	2	1	3
Total	124	70	133
Change in unrealized investment gains and losses:
Unrealized gains and (losses) on investments available for sale	345	(405)	250
OCI, portion attributable to Parent	188	(218)	130
OCI, portion attributable to Parent	537	(618)	370
Fixed Maturities
Realized investment gains and losses:
Gross realized gains	26	18	21
Gross realized losses	(1)	0	(3)
Other-than-temporary impairments	(2)	(18)	(15)
Change in unrealized investment gains and losses:
Unrealized gains and (losses) on investments available for sale	(40)	(263)	106
Equity Securities
Realized investment gains and losses:
Gross realized gains	152	129	136
Gross realized losses	(53)	(26)	0
Other-than-temporary impairments	0	(34)	(9)
Change in unrealized investment gains and losses:
Unrealized gains and (losses) on investments available for sale	571	(362)	278
Accumulated Net Unrealized Investment Gain (Loss)
Change in unrealized investment gains and losses:
OCI, portion attributable to Parent	186	(220)	134
OCI, portion attributable to Parent	$ 345	$ (405)	$ 250