Premium Deficiency Reserve (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011
Premium Deficiency Reserve [Abstract]
Present value of expected future paid losses and expenses, net of expected future premium	$ (865,000,000)		$ (1,039,000,000)		$ (865,000,000)		$ (1,039,000,000)		$ (961,000,000)
Established loss reserves	781,000,000		892,000,000		781,000,000		892,000,000		826,000,000
Net deficiency	(84,132,000)		(147,000,000)		(84,132,000)		(147,000,000)
Change in premium deficiency reserve, excluding prior period adjustments	9,000,000		12,000,000		51,000,000		32,000,000
Premium Deficiency Reserve [Roll Forward]
Premium Deficiency reserve at beginning of period	(93,000,000)		(159,000,000)		(134,817,000)		(179,000,000)
Paid claims and loss adjustment expenses	67,000,000		85,000,000		219,000,000		257,000,000
Decrease in loss reserves	(25,000,000)		(8,000,000)		(45,000,000)		(182,000,000)
Premium earned	(25,000,000)		(30,000,000)		(77,000,000)		(91,000,000)
Effects of present valuing on future premiums, losses and expenses	(4,000,000)		(6,000,000)		(8,000,000)		(15,000,000)
Change in premium deficiency reserve to reflect actual premium, losses and expenses recognized	13,000,000		41,000,000		89,000,000		(31,000,000)
Change in premium deficiency reserve to reflect change in assumptions relating to future premiums, losses, expenses and discount rate	(4,000,000)	[1]	(29,000,000)	[1]	(38,000,000)	[1]	63,000,000	[1]
Premium Deficiency Reserve at end of period	$ (84,132,000)		$ (147,000,000)		$ (84,132,000)		$ (147,000,000)

[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.