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

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swaptions (Details)

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swaptions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative, Notional Amount	$ (33,709,043)invest_DerivativeNotionalAmount	$ (48,115,523)invest_DerivativeNotionalAmount	$ (43,576,146)invest_DerivativeNotionalAmount	$ (37,366,610)invest_DerivativeNotionalAmount
Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Notional Amount	(12,960,000)	(12,410,000)	(9,500,000)	(5,130,000)
Variable Income Interest Rate [Member] \| Long [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(259,328)	(255,358)
Derivative, Fair Value, Net	(112,094)	(130,120)
Derivative, Average Remaining Period Until Maturity	53.14	56.62
Variable Income Interest Rate [Member] \| Long [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	6.9	7.4
Derivative, Notional Amount	(9,210,000)	(8,210,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	4.01%	4.116%
Variable Income Interest Rate [Member] \| Long [Member] \| Six Months or Longer Remaining Maturity [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(259,328)	(255,358)
Derivative, Fair Value, Net	(112,094)	(130,120)
Derivative, Average Remaining Period Until Maturity	53.14	56.62
Variable Income Interest Rate [Member] \| Long [Member] \| Six Months or Longer Remaining Maturity [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	6.9	7.4
Derivative, Notional Amount	(9,210,000)	(8,210,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	4.01%	4.116%
Variable Income Interest Rate [Member] \| Short [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(81,248)	(81,248)
Derivative, Fair Value, Net	(14,500)	(19,990)
Derivative, Average Remaining Period Until Maturity	27.02	30.02
Variable Income Interest Rate [Member] \| Short [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	10.0	10.0
Derivative, Notional Amount	(800,000)	(800,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	3.438%	3.438%
Variable Income Interest Rate [Member] \| Short [Member] \| Six Months or Longer Remaining Maturity [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(81,248)	(81,248)
Derivative, Fair Value, Net	(14,500)	(19,990)
Derivative, Average Remaining Period Until Maturity	27.02	30.02
Variable Income Interest Rate [Member] \| Short [Member] \| Six Months or Longer Remaining Maturity [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	10.0	10.0
Derivative, Notional Amount	(800,000)	(800,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	3.438%	3.438%
Fixed Income Interest Rate [Member] \| Long [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(26,013)	(10,715)
Derivative, Fair Value, Net	(6,914)	(6,462)
Derivative, Average Remaining Period Until Maturity	3.99	3.38
Fixed Income Interest Rate [Member] \| Long [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	6.7	5.0
Derivative, Notional Amount	(4,550,000)	(5,000,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	1.396%	1.352%
Fixed Income Interest Rate [Member] \| Long [Member] \| Less Than Six Months Remaining Maturity [Member] \| Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative, Cost	(26,013)	(10,715)
Derivative, Fair Value, Net	(6,914)	(6,462)
Derivative, Average Remaining Period Until Maturity	3.99	3.38
Fixed Income Interest Rate [Member] \| Long [Member] \| Less Than Six Months Remaining Maturity [Member] \| Underlying Swap [Member]
Derivative [Line Items]
Derivative, Average Remaining Period Until Maturity	6.7	5.0
Derivative, Notional Amount	$ (4,550,000)	$ (5,000,000)
Derivative, Description of Variable Reference Rate	3M Libor	3M Libor
Derivative, Average Fixed Interest Rate	1.396%	1.352%