CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ 870,278		$ 901,806
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Amortization of Investment premiums and discounts, net	421,057		280,336
Amortization of intangibles	323		591
Amortization of deferred expenses	2,038		900
Amortization of contingent beneficial conversion feature on convertible senior notes	3,324		7,828
Net (gains) losses on sales of Agency mortgage-backed securities and debentures	(182,843)		(80,299)
Stock option and long-term compensation expense	817		1,849
Unrealized (gains) losses on interest rate swaps	(325,734)		(341,639)
Net unrealized (gains) losses on interest-only Agency mortgage-backed securities	(80,127)		(30,877)
Net (gains) losses on trading assets	14,829		(2,871)
Proceeds from repurchase agreements from RCap	237,569,485		127,052,942
Payments on repurchase agreements from RCap	(238,600,415)		(122,741,955)
Proceeds from reverse repurchase agreements to RCap	104,959,663		54,896,766
Payments on reverse repurchase agreements to RCap	(108,104,936)		(56,577,802)
Proceeds from reverse repurchase agreements to Shannon	376,198		93,892
Payments on reverse repurchase agreements to Shannon	(353,295)		(92,591)
Proceeds from securities borrowed	53,799,157		6,683,283
Payments on securities borrowed	(54,326,700)		(6,877,004)
Proceeds from securities loaned	110,725,140		32,002,954
Payments on securities loaned	(110,203,395)		(31,931,006)
Proceeds from U.S. Treasury Securities	21,683,636		15,808,494
Payments on U.S. Treasury Securities	(22,157,117)		(14,086,314)
Net payments on derivatives	(1,490)		849
Net change in:
Other assets	(14,779)		(5,918)
Accrued interest and dividend receivable	22,616		(10,568)
Advisory and service fees receivable	4,913		(58)
Accrued interest payable	(11,147)		(9,857)
Accounts payable and other liabilities	26,250		50,704
Net cash provided by (used in) operating activities	(3,882,254)		4,994,435
Cash flows from investing activities:
Payments on purchases of Agency mortgage-backed securities and debentures	(17,699,472)		(20,099,149)
Proceeds from sales of Agency mortgage-backed securities and debentures	15,484,409		4,770,341
Principal payments on Agency mortgage-backed securities	8,514,074		7,376,488
Proceeds from Agency debentures called	847,205		151,640
Payments on purchases of corporate debt	(3,483)
Principal payments on corporate debt	911		1,335
Net gains (losses) on other derivative securities	7,465
Earn out payment			(13,387)
Net cash provided by (used in) investing activities	7,151,109		(7,812,732)
Cash flows from financing activities:
Proceeds from repurchase agreements	101,631,583		82,930,109
Principal payments on repurchase agreements	(103,063,408)		(79,618,116)
Proceeds from exercise of stock options	265		1,842
Net proceeds from direct purchases and dividend reinvestments	761
Net (payments) proceeds from follow-on offerings			(231)
Net payment on share repurchase	(141,149)
Dividends paid	(450,146)		(556,744)
Net cash provided by (used in) financing activities	(2,022,094)		2,756,860
Net (decrease) increase in cash and cash equivalents	1,246,761		(61,437)
Cash and cash equivalents, beginning of period	615,789	[1]	994,198
Cash and cash equivalents, end of period	1,862,550		932,761
Supplemental disclosure of cash flow information:
Interest received	1,188,202		1,125,003
Dividends received	7,097		8,283
Fees received	18,453		20,708
Interest paid (excluding interest paid on interest rate swaps)	184,426		134,099
Net interest paid on interest rate swaps	226,463		220,615
Taxes paid	2,382		21,401
Noncash investing activities:
Receivable for Investments sold	1,292,478		454,278
Payable for Investments purchased	3,203,461		5,708,412
Net change in unrealized loss on available-for-sale securities and interest rate swaps, net of reclassification adjustment	(1,049,994)		(242,558)
Noncash financing activities:
Dividends declared, not yet paid	426,173		534,401
Conversion of Series B cumulative preferred stock			32,232
Contingent beneficial conversion feature on Convertible Senior Notes	$ 3,963		$ 23,321

[1] Derived from the audited consolidated financial statements at December 31, 2012.