Schedule II Financial Information of Registrant Parent Company Statement of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net (loss) income	$ (451,468)		$ 302,150		$ (1,805,867)
Change in other assets	7,706		65,388		(34,405)
Change in accounts payable and accrued expenses	19,164		53,836		(20,014)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Proceeds from sales of fixed-maturity investments available for sale	79,534		136,217		1,218,460
Sales/redemptions of trading securities	6,004,371		6,028,267		4,735,215
Purchases of trading securities	(5,895,099)		(5,456,565)		(6,126,303)
Sales and redemptions of short-term investments, net	484,347		276,082		(86,071)
Purchases of property and equipment, net	(910)		(2,976)		(2,516)
Net Cash Provided by (Used in) Investing Activities	661,073		1,072,655		(47,785)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Dividends paid	(1,335)		(1,330)		(1,202)
Redemption of long-term debt	(153,261)		(160,000)		(29,348)
Proceeds from issuance of common stock	0		0		525,887
Net Cash Provided by (Used in) Financing Activities	(154,596)		(161,326)		886,647
Increase (decrease) in cash	(4,034)		15,255		(21,240)
Cash and Cash Equivalents, at Carrying Value	31,555		35,589		20,334
Parent Company
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net (loss) income	(451,468)		302,150		(1,805,867)
Net gains on other investments	(1,821)		(24,603)		(61,120)
Gain on the repurchase of long-term debt	(16,175)		0		(2,496)
Equity in undistributed net loss (income) of subsidiaries and affiliates (1)	505,267	[1]	(495,954)	[1]	2,049,175	[1]
(Decrease) increase in federal income taxes	(7,145)		49,396		(274,778)
Change in other assets	895		13,384		35,797
Change in accounts payable and accrued expenses	25,336		90,895		(20,711)
Net Cash Provided by (Used in) Operating Activities	54,889		(64,732)		(80,000)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Proceeds from sales of fixed-maturity investments available for sale	0		0		4,083
Sales/redemptions of trading securities	153,992		151,840		57,989
Purchases of trading securities	(3)		(32,825)		(455,724)
Sales and redemptions of short-term investments, net	41,042		156,665		(230,392)
Sales (purchases) of other invested assets, net	8,709		0		(25,000)
Purchases of property and equipment, net	(1,124)		(523)		(1,367)
Capital Contributions	(100,384)	[1]	(50,587)	[1]	(423,146)	[1]
Proceeds from Contributions from Affiliates	0		0		268,530
Net Cash Provided by (Used in) Investing Activities	102,232		224,570		(805,027)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Dividends paid	(1,335)		(1,330)		(1,202)
Issuance of long-term debt	0		0		391,310
Redemption of long-term debt	(153,261)		(160,000)		(29,348)
Proceeds from issuance of common stock	0		0		525,887
Net Cash Provided by (Used in) Financing Activities	(154,596)		(161,330)		886,647
Increase (decrease) in cash	2,525		(1,492)		1,620
Cash and Cash Equivalents, at Carrying Value	$ 2,978		$ 453		$ 1,945

[1] See Note A.