CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	7.875% Series A Cumulative Redeemable Preferred Stock	7.625% Series C Cumulative Redeemable Preferred Stock	7.50% Series D Cumulative Redeemable Preferred Stock	6.00% Series B Cumulative Convertible Preferred Stock	Common Stock Par Value	Common Stock Par Value 6.00% Series B Cumulative Convertible Preferred Stock	Additional Paid-In Capital	Additional Paid-In Capital 6.00% Series B Cumulative Convertible Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated Deficit 7.875% Series A Cumulative Redeemable Preferred Stock	Accumulated Deficit 7.625% Series C Cumulative Redeemable Preferred Stock	Accumulated Deficit 7.50% Series D Cumulative Redeemable Preferred Stock	Accumulated Deficit 6.00% Series B Cumulative Convertible Preferred Stock	7.875% Series A Cumulative Redeemable Preferred Stock	7.625% Series C Cumulative Redeemable Preferred Stock	7.625% Series C Cumulative Redeemable Preferred Stock	7.50% Series D Cumulative Redeemable Preferred Stock	7.50% Series D Cumulative Redeemable Preferred Stock
Beginning balance at Dec. 31, 2010	$ 9,864,900,000					$ 6,316,000		$ 9,175,245,000		$ 1,164,642,000	$ (658,391,000)					$ 177,088,000
Net income (loss)	344,461,000										344,461,000
Unrealized gains (losses) on available-for-sale securities	2,036,894,000									2,036,894,000
Unrealized (gains) losses on interest rate swaps	14,298,000									14,298,000
Reclassification adjustment for net (gains) losses included in net income (loss)	(206,846,000)									(206,846,000)
Exercise of stock options	8,953,000					7,000		8,946,000
Stock compensation expense	5,269,000					3,000		5,266,000
Net proceeds from direct purchase and dividend reinvestment	455,547,000					262,000		455,285,000
Conversion of Series B cumulative preferred stock	7,759,000				7,759,000		9,000		7,750,000
Contingent beneficial conversion feature on 4% Convertible Senior Notes	67,637,000							67,637,000
Preferred dividends declared		(14,593,000)			(2,261,000)							(14,593,000)			(2,261,000)
Common dividends declared	(2,173,222,000)										(2,173,222,000)
Net proceeds from follow-on offering	5,351,846,000					3,105,000		5,348,741,000
Ending balance at Dec. 31, 2011	15,760,642,000					9,702,000		15,068,870,000		3,008,988,000	(2,504,006,000)					177,088,000
Preferred dividends declared					(2,300,000)
Ending balance at Jan. 03, 2012
Beginning balance at Dec. 31, 2011	15,760,642,000					9,702,000		15,068,870,000		3,008,988,000	(2,504,006,000)					177,088,000
Net proceeds from Cumulative Redeemable Preferred Stock offering																		290,514,000		445,457,000
Net income (loss)	1,735,900,000										1,735,900,000
Unrealized gains (losses) on available-for-sale securities	482,765,000									482,765,000
Reclassification adjustment for net (gains) losses included in net income (loss)	(438,511,000)									(438,511,000)
Exercise of stock options	8,438,000					6,000		8,432,000
Stock compensation expense	5,584,000							5,584,000
Net proceeds from direct purchase and dividend reinvestment	2,794,000					2,000		2,792,000
Conversion of Series B cumulative preferred stock	32,272,000				32,272,000		40,000		32,232,000
Contingent beneficial conversion feature on 4% Convertible Senior Notes	61,725,000							61,725,000
Disposal of subsidiary	5,223,000										5,223,000
Preferred dividends declared		(14,593,000)	(14,297,000)	(10,351,000)	(289,000)							(14,593,000)	(14,297,000)	(10,351,000)	(289,000)
Common dividends declared	(1,989,690,000)										(1,989,690,000)
Equity component on 5% Convertible Senior Notes	11,717,000							11,717,000
Offering expenses	(248,000)							(248,000)
Extinguishment of convertible debt	(53,558,000)							(53,558,000)
Buyback of common stock	(397,050,000)					(278,000)		(396,772,000)
Ending balance at Dec. 31, 2012	15,924,444,000					9,472,000		14,740,774,000		3,053,242,000	(2,792,103,000)					177,088,000	290,514,000		445,457,000
Net income (loss)	3,729,698,000										3,729,698,000
Unrealized gains (losses) on available-for-sale securities	(5,378,089,000)									(5,378,089,000)
Reclassification adjustment for net (gains) losses included in net income (loss)	(424,086,000)									(424,086,000)
Exercise of stock options	2,204,000					2,000		2,202,000
Stock compensation expense	2,547,000					(2,000)		2,549,000
Net proceeds from direct purchase and dividend reinvestment	2,855,000					2,000		2,853,000
Contingent beneficial conversion feature on 4% Convertible Senior Notes	17,383,000							17,383,000
Disposal of subsidiary	20,923,000										20,923,000
Preferred dividends declared		(14,593,000)	(22,875,000)	(34,500,000)								(14,593,000)	(22,875,000)	(34,500,000)
Common dividends declared	(1,420,856,000)										(1,420,856,000)
Ending balance at Dec. 31, 2013	$ 12,405,055,000					$ 9,474,000		$ 14,765,761,000		$ (2,748,933,000)	$ (534,306,000)					$ 177,088,000	$ 290,514,000		$ 445,457,000