CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash Flows From Operating Activities:
Net income	$ 245,850	$ 208,181
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of MBS	(4,196)	(33,739)
Losses on termination of repurchase agreements		26,815
Other-than-temporary impairment charges	6,383	5,412
Net (accretion of purchase discounts)/amortization of purchase premiums	(6,380)	5,404
(Increase)/decrease in interest receivable	(6,125)	7,478
Depreciation and amortization on real estate and other assets	2,263	483
Unrealized losses/(gains) and other on Linked Transactions	4,831	(25,909)
Increase in prepaid and other assets and other	(47)	(53)
Increase/(decrease) in accrued expenses and other liabilities	37	(3,593)
Decrease in accrued interest payable	(529)	(5,877)
Equity-based compensation expense and other	2,983	2,190
Net cash provided by operating activities	245,070	186,792
Cash Flows From Investing Activities:
Principal payments on MBS	1,688,520	2,524,021
Proceeds from sale of MBS	76,495	939,119
Purchases of MBS	(4,430,941)	(2,492,909)
Net additions to leasehold improvements, furniture, fixtures and real estate investment	(2,004)	(276)
Net cash (used in)/provided by investing activities	(2,667,930)	969,955
Cash Flows From Financing Activities:
Principal payments on repurchase agreements	(43,843,055)	(39,524,402)
Proceeds from borrowings under repurchase agreements	45,821,751	38,324,022
Proceeds from issuance of securitized debt	963,255
Principal payments on securitized debt	(225,782)
Payments to terminate repurchase agreements		(26,815)
Payments made for resecuritization related costs	(6,981)
Cash disbursements on financial instruments underlying Linked Transactions	(2,051,908)	(1,088,668)
Cash received from financial instruments underlying Linked Transactions	1,464,965	962,012
Payments made for margin calls on repurchase agreements and interest rate swaps ("Swaps")	(8,460)	(435,507)
Proceeds from reverse margin calls on repurchase agreements and Swaps	25,914	461,850
Payment made to purchase interest rate swaptions ("Swaptions")	(915)
Proceeds from issuances of common stock	605,765	370
Dividends paid on preferred stock	(6,120)	(6,120)
Dividends paid on common stock and DERs	(239,786)	(196,881)
Principal amortization and prepayment on mortgage loan		(9,143)
Net cash provided by/(used in) financing activities	2,498,643	(1,539,282)
Net increase/(decrease) in cash and cash equivalents	75,783	(382,535)
Cash and cash equivalents at beginning of period	345,243	653,460
Cash and cash equivalents at end of period	421,026	270,925
Non-cash Investing and Financing Activities:
MBS recorded upon de-linking of Linked Transactions	744,231	112,835
Repurchase agreements recorded upon de-linking of Linked Transactions	46,698
Dividends and DERs declared and unpaid	$ 90,200	$ 538