TWO Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Schedule of Repurchase Agreement Counterparties with Whom Repurchase Agreements Exceed 10 Percent of Stockholders' Equity (Details)

Schedule of Repurchase Agreement Counterparties with Whom Repurchase Agreements Exceed 10 Percent of Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 13,094,878	$ 12,932,463
Repurchase Agreement Counterparty, Royal Bank of Canada [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	1,284,065	1,373,549
Repurchase Agreement Counterparty, Amount at Risk	344,167	401,194
Repurchase Agreement Counterparty, Percent of Equity at Risk	8.00%	10.00%
Repurchase Agreement Counterparty, Weighted Average Days to Maturity	73.1	83.8
Repurchase Agreement Counterparty, Barclays Capital [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	799,269	1,346,085
Repurchase Agreement Counterparty, Amount at Risk	298,274	365,879
Repurchase Agreement Counterparty, Percent of Equity at Risk	7.00%	9.00%
Repurchase Agreement Counterparty, Weighted Average Days to Maturity	45.2	50.5
Repurchase Agreement Counterparty, All Other Counterparties [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	10,010,294	9,215,329
Repurchase Agreement Counterparty, Amount at Risk	990,372	907,066
Repurchase Agreement Counterparty, Percent of Equity at Risk	24.00%	22.00%
Repurchase Agreement Counterparty, Weighted Average Days to Maturity	66.5	57.7
Number of Repurchase Agreement Counterparties with Whom Repurchase Agreements Are Less Than 10 Percent of Stockholders' Equity	22	23
Repurchase Agreement Counterparty, Excluding Repurchase Agreements Collateralized by U.S. Treasuries [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	12,093,628	11,934,963
Repurchase Agreement Counterparty, Amount at Risk	1,632,813	1,674,139
US Treasury Securities [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	2,001,250	1,996,250
Maturity on Demand [Member]
Repurchase Agreement Counterparty [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 1,001,250	$ 997,500