Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Statements of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows from Operating Activities
Net income (loss)	$ 937	$ 628	$ 612
Adjustments to reconcile net income (loss) to net cash flows provided (used) by operating activities:
Net realized investment (gains) losses	(31)	(63)	2
Other, net	10	14	10
Total adjustments	267	622	1,076
Net cash flows provided (used) by operating activities-total	1,204	1,250	1,702
Cash Flows from Investing Activities
Change in short term investments	425	(7)	566
Other, net	11	16	1
Net cash flows provided (used) by investing activities-total	(898)	(934)	(1,060)
Cash Flows from Financing Activities
Dividends paid to common stockholders	(216)	(162)	(108)
Proceeds from the issuance of debt			396
Repayment of debt	(13)	(70)	(451)
Stock options exercised	2	1	2
Other, net	(37)	(8)	(8)
Net cash flows provided (used) by financing activities-total	(264)	(239)	(644)
Net change in cash	39	81	(2)
Cash, beginning of year	156	75	77
Cash, end of year	195	156	75
Parent Company [Member]
Cash Flows from Operating Activities
Net income (loss)	937	628	612
Adjustments to reconcile net income (loss) to net cash flows provided (used) by operating activities:
Equity in net income (loss) of subsidiaries	(1,068)	(635)	(704)
Dividends received from subsidiaries	400	450
Net realized investment (gains) losses	(4)	(4)	9
Other, net	8	19	55
Total adjustments	(664)	(170)	(640)
Net cash flows provided (used) by operating activities-total	273	458	(28)
Cash Flows from Investing Activities
Proceeds from fixed maturity securities	1	1	1
Change in short term investments	(57)	(156)	(77)
Capital contributions to subsidiaries	(12)	(399)	(38)
Return of capital from subsidiaries			6
Repayment of surplus note by subsidiary		250	250
Other, net	4	4	1
Net cash flows provided (used) by investing activities-total	(64)	(300)	143
Cash Flows from Financing Activities
Dividends paid to common stockholders	(216)	(162)	(108)
Proceeds from the issuance of debt			396
Repayment of debt	(3)		(409)
Stock options exercised	2	1	5
Other, net	9	3	1
Net cash flows provided (used) by financing activities-total	(208)	(158)	(115)
Net change in cash	1
Cash, beginning of year
Cash, end of year	$ 1