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

Schedule of Notional Amounts of Derivative Positions (Details)

Schedule of Notional Amounts of Derivative Positions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	$ (48,115,523)invest_DerivativeNotionalAmount	$ (37,366,610)invest_DerivativeNotionalAmount
Derivative, Notional Amount, Additions	(12,292,267)two_DerivativeNotionalAmountAdditions	(15,835,110)two_DerivativeNotionalAmountAdditions
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(26,698,747)	(9,625,574)
Derivative, Notional Amount, Ending Balance	(33,709,043)invest_DerivativeNotionalAmount	(43,576,146)invest_DerivativeNotionalAmount
Derivative, Average Notional Amount	(42,996,135)two_DerivativeAverageNotionalAmount	(39,708,009)two_DerivativeAverageNotionalAmount
Gain (Loss) on Sale of Derivatives	2,893us-gaap_GainLossOnSaleOfDerivatives	957us-gaap_GainLossOnSaleOfDerivatives
Inverse Interest-Only Securities [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(1,168,226)	(1,525,845)
Derivative, Notional Amount, Additions	0	0
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(62,016)	(113,471)
Derivative, Notional Amount, Ending Balance	(1,106,210)	(1,412,374)
Derivative, Average Notional Amount	(1,138,468)	(1,470,667)
Gain (Loss) on Sale of Derivatives	0	193
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(18,584,000)	(19,619,000)
Derivative, Notional Amount, Additions	(5,620,000)	(2,944,148)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(4,275,000)	(900,000)
Derivative, Notional Amount, Ending Balance	(19,929,000)	(21,663,148)
Derivative, Average Notional Amount	(18,238,389)	(19,156,878)
Gain (Loss) on Sale of Derivatives	(1,070)	(22)
Credit Default Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(125,000)	(427,073)
Derivative, Notional Amount, Additions	0	0
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	0	(302,073)
Derivative, Notional Amount, Ending Balance	(125,000)	(125,000)
Derivative, Average Notional Amount	(125,000)	(179,418)
Gain (Loss) on Sale of Derivatives	0	(13,705)
Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(12,410,000)	(5,130,000)
Derivative, Notional Amount, Additions	(5,550,000)	(3,900,000)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(5,000,000)	(470,000)
Derivative, Notional Amount, Ending Balance	(12,960,000)	(9,500,000)
Derivative, Average Notional Amount	(12,851,667)	(8,979,111)
Gain (Loss) on Sale of Derivatives	12,845	(1,219)
Forward Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(1,325,000)	(603,000)
Derivative, Notional Amount, Additions	(6,933,000)	(892,000)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(5,762,000)	(733,000)
Derivative, Notional Amount, Ending Balance	(2,496,000)	(1,022,000)
Derivative, Average Notional Amount	(2,121,700)	(526,444)
Gain (Loss) on Sale of Derivatives	(17,364)	11,853
Options Held [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(2,000,000)	0
Derivative, Notional Amount, Additions	(250,000)	(1,500,000)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(4,750,000)	0
Derivative, Notional Amount, Ending Balance	(2,500,000)	(1,500,000)
Derivative, Average Notional Amount	(8,333)	(255,556)
Gain (Loss) on Sale of Derivatives	(3,047)	0
Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(14,000,000)	(10,000,000)
Derivative, Notional Amount, Additions	(6,000,000)	(8,000,000)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(17,000,000)	(8,000,000)
Derivative, Notional Amount, Ending Balance	(3,000,000)	(10,000,000)
Derivative, Average Notional Amount	(6,988,889)	(10,000,000)
Gain (Loss) on Sale of Derivatives	6,384	3,887
Total Return Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(598,459)	(49,629)
Derivative, Notional Amount, Additions	(676,633)	(197,012)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(397,563)	(2,654)
Derivative, Notional Amount, Ending Balance	(877,529)	(243,987)
Derivative, Average Notional Amount	(875,346)	(153,910)
Gain (Loss) on Sale of Derivatives	4,202	0
Forward Purchase Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount, Beginning Balance	(554,838)	(12,063)
Derivative, Notional Amount, Additions	(1,128,634)	(185,950)
Derivative, Notional Amount, Settlement Termination Expiration or Exercise	(976,168)	(44,376)
Derivative, Notional Amount, Ending Balance	(707,304)	(153,637)
Derivative, Average Notional Amount	(648,343)	(38,913)
Gain (Loss) on Sale of Derivatives	$ 943	$ (30)