CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Cash flows from operating activities:
Net income (loss)	$ 224,758	$ (921,813)	$ 1,035,405		$ (101,101)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Amortization of investment premiums and discounts, net	455,493	200,942	1,038,598		502,186
Amortization of intangibles	634	676	1,858		1,511
Amortization of deferred expenses	2,189	900	4,927		2,700
Amortization of contingent beneficial conversion feature and equity component on convertible senior notes	1,438	1,898	15,498		1,898
Net (gains) losses on disposal of investments	(142,172)	(91,668)	(317,308)		(126,189)
Net loss on extinguishment of 4% Convertible Senior Notes	87,328		87,328
Stock option and long-term compensation expense	997	1,403	3,857		3,862
Unrealized (gains) losses on interest rate swaps	104,197	1,505,333	373,773		1,802,968
Net unrealized (gains) losses on interest-only Agency mortgage-backed securities	33,563	39,321	28,789		39,045
Net (gains) losses on trading assets	(1,368)	(1,942)	(5,344)		(15,042)
Gain on investment in affiliate, equity method					(98)
Unrealized (gains) losses on equity securities		63			63
Proceeds from repurchase agreements from RCap	168,905,024	157,069,300	509,943,940		720,578,286
Payments on repurchase agreements from RCap	(166,150,546)	(156,683,356)	(502,959,819)		(719,466,382)
Proceeds from reverse repurchase agreements to RCap	113,457,928	27,610,583	299,139,881		132,302,897
Payments on reverse repurchase agreements to RCap	(113,053,067)	(27,359,741)	(299,884,954)		(131,634,729)
Proceeds from reverse repurchase agreements to Shannon	185,640	58,848	409,380		65,893
Payments on reverse repurchase agreements to Shannon	(177,414)	(76,140)	(415,825)		(88,213)
Proceeds from securities borrowed	26,397,098	12,445,883	45,821,749		14,898,651
Payments on securities borrowed	(26,534,463)	(12,978,764)	(46,495,709)		(15,734,785)
Proceeds from securities loaned	59,324,108	12,398,720	125,183,976		14,902,887
Payments on securities loaned	(59,188,247)	(11,938,989)	(124,739,909)		(14,213,667)
Proceeds from U.S. Treasury Securities	13,085,890	(5,303,369)	44,183,569		(18,193,311)
Payments on U.S. Treasury Securities	(13,407,718)	5,716,809	(45,248,472)		18,514,722
Net payments on derivatives	(648)	(1,771)	(18,108)		(4,545)
Net change in:
Other assets	(3,226)	(4,795)	(1,072)		(4,110)
Accrued interest and dividend receivable	(4,812)	(22,148)	(16,942)		(62,792)
Advisory and service fees receivable	472	10	(721)		(3,484)
Accrued interest payable	6,683	5,618	42,537		12,605
Accounts payable and other liabilities	(11,767)	(4,058)	75,863		65,916
Net cash provided by (used in) operating activities	3,597,992	1,667,753	7,286,745		4,047,642
Cash flows from investing activities:
Payments on purchases of Agency mortgage-backed securities and debentures	(21,398,098)	(17,054,754)	(59,518,222)		(49,344,466)
Proceeds from sales of Agency mortgage-backed securities and debentures	7,810,451	3,568,718	17,725,948		9,001,949
Principal payments on Agency mortgage-backed securities	9,943,910	5,074,528	25,197,941		14,429,098
Proceeds from Agency debentures called	327,385	288,925	1,177,548		906,523
Payments on purchase of corporate debt	(23,520)		(33,420)		(7,425)
Proceeds from corporate debt called	19,165		19,165
Principal payments on corporate debt	565		2,025		1,155
Net gains (losses) on other derivative securities					11,518
Earn out payment			(13,387)
Purchase of investment in affiliate					(57,500)
Purchase of customer relationships					(3,555)
Proceeds from sales of equity securities		(3,990)	4,048		(3,990)
Net cash provided by (used in) investing activities	(3,320,142)	(8,126,573)	(15,438,354)		(25,066,693)
Cash flows from financing activities:
Proceeds from repurchase agreements	91,857,968	72,790,611	258,994,965		200,627,105
Principal payments on repurchase agreements	(90,340,097)	(65,127,815)	(249,043,825)		(180,776,641)
Proceeds from exercise of stock options	670	1,752	6,061		7,864
Net proceeds from issuance of 5% Convertible Senior Notes offering			727,500
Net proceeds from direct purchases and dividend reinvestments	1,134		1,979		455,706
Net payment from extinguishment of 4% Convertible Senior Notes	(357,220)		(357,220)
Net (payment) proceeds from follow-on offerings	(17)	2,410,435	(248)		5,351,846
Dividends paid	(545,265)	(544,141)	(1,642,918)		(1,455,589)
Net cash provided by (used in) financing activities	1,062,630	9,530,842	9,422,265		24,210,291
Net (decrease) increase in cash and cash equivalents	1,340,480	3,072,022	1,270,656		3,191,240
Cash and cash equivalents, beginning of period	924,374		994,198	[1]	282,626
Cash and cash equivalents, end of period	2,264,854	3,473,866	2,264,854		3,473,866
Supplemental disclosure of cash flow information:
Interest received	1,203,598	1,107,518	3,514,893		3,168,555
Dividends received	6,621	8,230	22,425		23,170
Fees received	21,506	20,838	63,008		55,261
Interest paid (excluding interest paid on interest rate swaps)	173,889	116,641	423,752		345,485
Net interest paid on interest rate swaps	224,155	229,109	665,508		644,962
Taxes paid	17,374	17,919	46,541		43,595
Noncash investing activities:
Receivable for investments sold	470,266	402,817	470,266		402,817
Payable for Investments purchased	16,107,038	5,852,986	16,107,038		5,852,986
Net change in unrealized loss on available-for-sale securities and interest rate swaps, net of reclassification adjustment	656,287	1,023,657	1,060,619		1,908,846
Noncash financing activities:
Dividends declared, not yet paid	487,237	581,752	487,237		581,752
Conversion of Series B cumulative preferred stock		6,295	32,272		6,368
Contingent beneficial conversion feature on 4% Convertible Senior Notes	(26,603)	44,853	19,738		44,853
Equity component of 5% Convertible Senior Notes	11,717		11,717
7.625% Series C Cumulative Redeemable Preferred Stock [Member]
Cash flows from financing activities:
Net proceeds from preferred stock offering			290,514
7.50% Series D Cumulative Redeemable Preferred Stock [Member]
Cash flows from financing activities:
Net proceeds from preferred stock offering	$ 445,457		$ 445,457

[1] Derived from the audited consolidated financial statements at December 31, 2011.