Investments (Investment Income Realized Investment Gains And Losses And Change In Unrealized Investment Gains And Losses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Investment income summarized by investment category:
Interest on fixed maturities	$ 420	$ 424	$ 423
Dividends on equity securities	115	104	99
Other investment income	3	4	4
Total	538	532	526
Less investment expenses	7	7	8
Total	531	525	518
Realized investment gains and losses summary:
Other	7	3	5
Unrealized gains on other	(21)	(11)	(4)
Realized gains on investments	42	70	159
Change in unrealized investment gains and losses and other summary:
Adjustment to deferred acquisition costs and life policy reserves	(28)	(14)	(9)
Pension obligations	(13)	(25)	3
Other	7	3	5
Income taxes on above	(124)	(71)	(78)
Unrealized gains on investments available-for-sale	428	309	383
Fixed Maturities [Member]
Realized investment gains and losses summary:
Gross realized gains	35	11	25
Gross realized losses			(12)
Other-than-temporary impairments	(1)	(5)	(3)
Change in unrealized investment gains and losses and other summary:
Unrealized gains on investments available-for-sale	176	200	154
Equity Securities [Member]
Realized investment gains and losses summary:
Securities with embedded derivatives	1	(1)	10
Other	2	6	(2)
Gross realized gains	39	151	174
Gross realized losses	(2)	(40)
Other-than-temporary impairments	(32)	(52)	(33)
Change in unrealized investment gains and losses and other summary:
Other	2	6	(2)
Unrealized gains on investments available-for-sale	$ 210	$ 39	$ 70