Offsetting Assets and Liabilities (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 counterparty		Dec. 31, 2012
Derivative hedging instruments, at fair value
Gross Amounts of Recognized Assets	$ 13,000,000		$ 203,000
Gross Amounts offset in the Consolidated Balance Sheets	0		0
Net Amounts of Assets Presented in the Consolidated Balance Sheet	13,000,000		203,000
Derivative Fair Value of Derivative Asset Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	(13,000,000)		(203,000)
Cash Collateral Received	0		0
Net Amount	0		0
Derivative hedging instruments, at fair value
Gross Amounts of Recognized Liabilities	28,217,000		63,034,000
Repurchase agreements
Gross Amounts of Recognized Liabilities	8,339,297,000	[1]	8,752,472,000	[1]
Gross Amounts Offset in the Consolidated Balance Sheet	0	[1]	0	[1]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	8,339,297,000	[1]	8,752,472,000	[1]
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments	(8,339,297,000)	[1],[2]	(8,752,472,000)	[1],[2]
Cash Collateral Pledged	0	[1],[2]	0	[1],[2]
Net Amount	0	[1]	0	[1]
Total
Gross Amounts of Recognized Liabilities	8,367,514,000		8,815,506,000
Gross Amounts Offset in the Consolidated Balance Sheet	0		0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	8,367,514,000		8,815,506,000
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments	(8,339,297,000)	[2]	(8,810,490,000)	[2]
Cash Collateral Pledged	(28,217,000)	[2]	(5,016,000)	[2]
Net Amount	0		0
Additional disclosures
Derivative, Collateral, Excess	9,300,000	[2],[3]
Fair value of securities pledged against the swaps	73,900,000		68,900,000
Fair value of securities pledged against the repurchase agreements	10,116,000,000		10,550,000,000
Number of repurchase agreement counterparties with unconditional right of setoff	1
Hedging instrument
Derivative hedging instruments, at fair value
Gross Amounts of Recognized Assets	13,000,000		203,000
Gross Amounts offset in the Consolidated Balance Sheets	0		0
Net Amounts of Assets Presented in the Consolidated Balance Sheet	13,000,000		203,000
Derivative Fair Value of Derivative Asset Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	(13,000,000)		(203,000)
Cash Collateral Received	0		0
Net Amount	0		0
Derivative hedging instruments, at fair value
Gross Amounts of Recognized Liabilities	28,217,000	[3]	63,034,000	[3]
Gross Amounts Offset in the Consolidated Balance Sheet	0	[3]	0	[3]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet	28,217,000	[3]	63,034,000	[3]
Gross Amounts Not Offset in the Consolidated Balance Sheet
Financial Instruments	0	[2],[3]	(58,018,000)	[2],[3]
Cash Collateral Pledged	(28,217,000)	[2],[3]	(5,016,000)	[2],[3]
Net Amount	$ 0	[3]	$ 0	[3]

[1] The fair value of securities pledged against the Company’s repurchase agreements was $10.116 billion and $10.550 billion at December 31, 2013 and 2012, respectively.

[2] Amounts disclosed in the Financial Instruments column of the table above represents collateral pledged that is available to be offset against liability balances associated with repurchase agreement and derivative transactions. Amounts disclosed in the Cash Collateral Pledged column of the table above represents amounts pledged as collateral against derivative transactions and as of December 31, 2013 excludes excess collateral of $9.3 million.

[3] The fair value of securities pledged against the Company’s Swaps was $73.9 million and $68.9 million at December 31, 2013 and 2012, respectively.