Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Maturities (Details) (Farmer Mac Guaranteed Securities and USDA Securities [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Due within one year, Amortized Cost	$ 904,030
Available-for-sale Securities, Due after one year through five years, Amortized Cost	3,153,604
Available-for-sale Securities, Due after five years through ten years, Amortized Cost	757,080
Available-for-sale Securities, Due after ten years, Amortized Cost	1,867,855
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Due within one year, Fair Value	913,404
Available-for-sale Securities, Due after one year through five years, Fair Value	3,181,924
Available-for-sale Securities, Due after five years through ten years, Fair Value	748,279
Available-for-sale Securities, Due after ten years, Fair Value	1,801,662
Available-for-sale Securities, Debt Maturities, Weighted-Average Yield, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Due within one year, Weighted-Average Yield	2.37%
Available-for-sale Securities, Due after one year through five years, Weighted-Average Yield	2.18%
Available-for-sale Securities, Due after five years through ten years, Weighted-Average Yield	2.02%
Available-for-sale Securities, Due after ten years, Weighted-Average Yield	2.59%
Available-for-sale Securities, Total Weighted-Average Yield	2.30%
Payment Guarantee [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Amortized Cost Basis	6,682,569	6,130,811
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale, at fair value	$ 6,645,269	$ 6,252,853

Available-for-sale Securities, Debt Maturities, after Ten Years, Weighted-Average Yield

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Available-for-sale Securities, Debt Maturities, Next Twelve Months, Weighted-Average Yield

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Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Weighted-Average Yield

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Available-for-sale Securities, Debt Maturities, Year Two Through Five, Weighted-Average Yield

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing after the tenth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the next fiscal year following the latest fiscal year.

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