CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 615,789	$ 994,198
Reverse repurchase agreements	1,811,095	860,866
Investments, at fair value:
U.S. Treasury Securities (including pledged assets of $752,076 and $352,820, respectively)	752,076	928,547
Securities borrowed	2,160,942	928,732
Agency mortgage-backed securities (including pledged assets of $107,466,084 and $90,406,535, respectively)	123,963,207	104,251,055
Agency debentures (including pledged assets of $981,727 and $567,383, respectively)	3,009,568	889,580
Investments in affiliates	234,120	211,970
Equity securities		3,891
Corporate debt, held for investment	63,944	52,073
Receivable for Investments sold	290,722
Accrued interest and dividends receivable	419,259	409,023
Receivable from Prime Broker		3,272
Receivable for advisory and service fees (including from affiliates of $14,077 and $16,245, respectively)	17,730	19,550
Intangible for customer relationships (net of accumulated amortization of $5,779 and $5,432, respectively)	6,989	10,807
Goodwill	55,417	42,030
Other derivative contracts, at fair value	9,830	113
Other assets	41,607	24,295
Total Assets	133,452,295	109,630,002
Liabilities:
U.S. Treasury Securities sold, not yet purchased, at fair value	495,437	826,912
Repurchase agreements	102,785,697	84,097,885
Securities loaned, at fair value	1,808,315	804,901
Payable for Investments purchased	8,256,957	4,315,796
Payable for share buyback program	141,149
Convertible Senior Notes	825,541	539,913
Accrued interest payable	186,896	138,965
Dividends payable	432,154	552,806
Interest rate swaps, at fair value	2,584,907	2,552,687
Accounts payable and other liabilities	10,798	7,223
Total Liabilities	117,527,851	93,837,088
Stockholders' Equity:
Common stock, par value $0.01 per share, 1,956,937,500 and 1,987,987,500 authorized, respectively, 947,213,204 and 970,161,647 issued and outstanding, respectively	9,472	9,702
Additional paid-in capital	14,740,774	15,068,870
Accumulated other comprehensive income (loss)	3,053,242	3,008,988
Accumulated deficit	(2,792,103)	(2,504,006)
Total Stockholders' Equity	15,924,444	15,760,642
Total Liabilities, Series B Cumulative Convertible Preferred Stock and Stockholders' Equity	133,452,295	109,630,002
6.00% Series B Cumulative Convertible Preferred Stock [Member]
Liabilities:
6.00% Series B Cumulative Convertible Preferred Stock: 4,600,000 shares authorized, 0 and 1,331,849 shares issued and outstanding, respectively		32,272
7.875% Series A Cumulative Redeemable Preferred Stock [Member]
Stockholders' Equity:
Cumulative Redeemable Preferred Stock	177,088	177,088
7.625% Series C Cumulative Redeemable Preferred Stock [Member]
Stockholders' Equity:
Cumulative Redeemable Preferred Stock	290,514
7.50% Series D Cumulative Redeemable Preferred Stock [Member]
Stockholders' Equity:
Cumulative Redeemable Preferred Stock	$ 445,457