Shareholders' Equity - Change in Accumulated Other Comprehensive Income by Component (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period			$ 160
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Net current period other comprehensive income	1	(3)	173	(309)
Balance at end of period	333		333
Net Unrealized Gains (Losses) on Investments with no OTTI
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	345	237	178	517
Other comprehensive income (loss) before reclassifications	(5)	(11)	164	(280)
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Other net realized investment gains (losses)	(5)	(2)	(9)	(16)
Interest expense	0	0	0	0
Total before tax	(5)	(2)	(9)	(16)
Tax (provision) benefit	2	1	4	4
Total amounts reclassified from AOCI, net of tax	(3)	(1)	(5)	(12)
Net current period other comprehensive income	(8)	(12)	159	(292)
Balance at end of period	337	225	337	225
Net Unrealized Gains (Losses) on Investments with OTTI
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(22)	(25)	(24)	(5)
Other comprehensive income (loss) before reclassifications	1	(2)	(8)	(34)
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Other net realized investment gains (losses)	20	7	37	24
Interest expense	0	0	0	0
Total before tax	20	7	37	24
Tax (provision) benefit	(7)	(3)	(13)	(8)
Total amounts reclassified from AOCI, net of tax	13	4	24	16
Net current period other comprehensive income	14	2	16	(18)
Balance at end of period	(8)	(23)	(8)	(23)
Cumulative Translation Adjustment
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	1	(12)	(3)	(6)
Other comprehensive income (loss) before reclassifications	(5)	7	(1)	1
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Other net realized investment gains (losses)	0	0	0	0
Interest expense	0	0	0	0
Total before tax	0	0	0	0
Tax (provision) benefit	0	0	0	0
Total amounts reclassified from AOCI, net of tax	0	0	0	0
Net current period other comprehensive income	(5)	7	(1)	1
Balance at end of period	(4)	(5)	(4)	(5)
Cash Flow Hedge
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	8	9	9	9
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Other net realized investment gains (losses)	0	0	0	0
Interest expense	0	0	0	(1)
Total before tax	0	0	0	(1)
Tax (provision) benefit	0	0	(1)	1
Total amounts reclassified from AOCI, net of tax	0	0	(1)	0
Net current period other comprehensive income	0	0	(1)	0
Balance at end of period	8	9	8	9
Total Accumulated Other Comprehensive Income
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	332	209	160	515
Other comprehensive income (loss) before reclassifications	(9)	(6)	155	(313)
Amounts Reclassified Out Of Other Comprehensive Income [Abstract]
Other net realized investment gains (losses)	15	5	28	8
Interest expense	0	0	0	(1)
Total before tax	15	5	28	7
Tax (provision) benefit	(5)	(2)	(10)	(3)
Total amounts reclassified from AOCI, net of tax	10	3	18	4
Net current period other comprehensive income	1	(3)	173	(309)
Balance at end of period	$ 333	$ 206	$ 333	$ 206