Premium Deficiency Reserve (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Premium Deficiency Reserve [Abstract]
Present value of expected future paid losses and expenses, net of expected future premium	$ (749,000,000)		$ (899,000,000)		$ (749,000,000)		$ (899,000,000)		$ (840,000,000)
Established loss reserves	688,000,000		806,000,000		688,000,000		806,000,000		766,000,000
Net deficiency	(60,848,000)		(93,000,000)		(60,848,000)		(93,000,000)
Change in premium deficiency reserve	11,000,000		27,000,000		13,000,000		42,000,000
Premium Deficiency Reserve [Roll Forward]
Premium Deficiency Reserve at beginning of period	(72,000,000)		(121,000,000)		(73,781,000)		(135,000,000)
Paid claims and loss adjustment expenses	63,000,000		76,000,000		121,000,000		152,000,000
Decrease in loss reserves	(48,000,000)		24,000,000		(78,000,000)		(20,000,000)
Premium earned	(25,000,000)		(25,000,000)		(48,000,000)		(53,000,000)
Effects of present valuing on future premiums, losses and expenses	(2,000,000)		2,000,000		(1,000,000)		2,000,000
Change in premium deficiency reserve to reflect actual premium, losses and expenses recognized	(12,000,000)		77,000,000		(6,000,000)		81,000,000
Change in premium deficiency reserve to reflect change in assumptions relating to future premiums, losses expenses and discount rate	23,000,000	[1]	(49,000,000)	[1]	19,000,000	[1]	(39,000,000)	[1]
Premium Deficiency Reserve at end of period	$ (60,848,000)		$ (93,000,000)		$ (60,848,000)		$ (93,000,000)

[1] A (negative) positive number for changes in assumptions relating to premiums, losses, expenses and discount rate indicates a (deficiency) redundancy of the prior premium deficiency reserve.