Loans and Commitments (Details) - USD ($) $ in Thousands		Feb. 29, 2016		Nov. 30, 2015	May. 31, 2015		Feb. 28, 2015
Loans outstanding
Total loans outstanding		$ 23,134,215	[1],[2]		$ 21,459,220	[1],[2]	$ 21,202,399
Deferred origination costs		9,884	[1]		9,797	[1]	$ 9,693
Loans to members	[1]	23,144,099			21,469,017
Unadvanced commitments
Total Unadvanced commitments		3,000			2,000
Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[2],[3]	13,312,420			14,129,750
CFC
Loans outstanding
Total loans outstanding	[1]	22,079,012			20,341,990
CFC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	12,400,440			12,875,542
CFC | Distribution
Loans outstanding
Total loans outstanding	[1]	17,700,859			16,095,043
CFC | Distribution | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	9,045,185			9,474,568
CFC | Power supply
Loans outstanding
Total loans outstanding	[1]	4,322,069			4,181,481
CFC | Power supply | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	3,219,631			3,273,501
CFC | Statewide and associate
Loans outstanding
Total loans outstanding	[1]	56,084			65,466
CFC | Statewide and associate | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	135,624			127,473
RTFC
Loans outstanding
Total loans outstanding	[1]	357,967			385,709
RTFC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	258,690			288,810
NCSC
Loans outstanding
Total loans outstanding	[1]	697,236			731,521
NCSC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	653,290			965,398
Loans Guaranteed by Farmer Mac
Loans outstanding
Total loans outstanding		511,000		$ 520,000
Long-term fixed-rate loans
Loans outstanding
Total loans outstanding	[1]	21,127,042			19,543,274
Long-term variable-rate loans
Loans outstanding
Total loans outstanding	[1]	718,193			698,495
Long-term variable-rate loans | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	4,402,860			4,835,623
Loans guaranteed by RUS
Loans outstanding
Total loans outstanding	[1]	174,990			179,241
Line of credit loans
Loans outstanding
Total loans outstanding	[1]	1,113,990			1,038,210
Line of credit loans | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	[1],[3]	$ 8,909,560			$ 9,294,127

[1] Includes nonperforming and restructured loans.

[2] Represents the unpaid principal balance excluding deferred loan origination costs.

[3] The interest rate on unadvanced commitments is not set until drawn; therefore, the long-term unadvanced loan commitments have been classified in this table as variable-rate unadvanced commitments. However, at the time of the advance, the borrower may select a fixed or a variable rate on the new loan.