Loans and Commitments (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014		Nov. 30, 2013	May 31, 2013		Feb. 28, 2013	Nov. 30, 2012	May 31, 2012
Loans outstanding
Total loans outstanding	$ 20,635,333	[1],[2]		$ 20,296,317	[1],[2]	$ 19,477,734
Deferred origination costs	9,731			9,557		8,414
Less: Allowance for loan losses	(56,040)		(55,199)	(54,325)		(148,411)	(148,737)	(143,326)
Loans to members, net	20,589,024			20,251,549		19,337,737
Unadvanced commitments
Total Unadvanced commitments				39,000
Nonperforming Financing Receivable
Loans outstanding
Total loans outstanding	10,845			15,497
Restructured financing receivable
Loans outstanding
Total loans outstanding	7,584			46,953
Unadvanced commitments
Loans outstanding
Deferred origination costs	0	[3]		0	[3]
Less: Allowance for loan losses	0	[3]		0	[3]
Loans to members, net	13,544,658	[3]		13,422,748	[3]
Unadvanced commitments
Total Unadvanced commitments	13,544,658	[2],[3]		13,422,748	[2],[3]
Unadvanced commitments | Nonperforming Financing Receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		0	[3]
Unadvanced commitments | Restructured financing receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		5,000	[3]
CFC
Loans outstanding
Total loans outstanding	19,400,546	[1],[2]		19,019,817	[1],[2]	19,445,360
Deferred origination costs	9,731					8,414
Less: Allowance for loan losses	(44,359)		(42,762)	(41,246)		(134,062)	(133,578)	(126,941)
Loans to members, net	20,559,045					19,305,363
CFC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	12,268,234	[2],[3]		12,196,431	[2],[3]
CFC | Distribution
Loans outstanding
Total loans outstanding	15,186,620	[2]		14,941,192	[2]
CFC | Distribution | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	9,115,128	[2],[3]		8,948,826	[2],[3]
CFC | Power supply
Loans outstanding
Total loans outstanding	4,149,104	[2]		4,007,669	[2]
CFC | Power supply | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	3,024,666	[2],[3]		3,145,518	[2],[3]
CFC | Statewide and associate
Loans outstanding
Total loans outstanding	64,822	[2]		70,956	[2]
CFC | Statewide and associate | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	128,440	[2],[3]		102,087	[2],[3]
RTFC
Loans outstanding
Total loans outstanding	455,492	[2]		503,359	[2]
RTFC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	312,466	[2],[3]		317,344	[2],[3]
NCSC
Loans outstanding
Total loans outstanding	779,295	[2]		773,141	[2]
NCSC | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	963,958	[2],[3]		908,973	[2],[3]
Long-term fixed-rate loans
Loans outstanding
Total loans outstanding	18,185,111	[2]		17,918,268	[2]
Long-term fixed-rate loans | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	0	[2],[3]		0	[2],[3]
Long-term fixed-rate loans | CFC | Restructured financing receivable
Loans outstanding
Total loans outstanding	7,584			46,953
Long-term fixed-rate loans | CFC | Unadvanced commitments | Restructured financing receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		0	[3]
Long-term fixed-rate loans | RTFC | Nonperforming Financing Receivable
Loans outstanding
Total loans outstanding	2,786			3,690
Long-term fixed-rate loans | RTFC | Unadvanced commitments | Nonperforming Financing Receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		0	[3]
Long-term variable-rate loans
Loans outstanding
Total loans outstanding	770,883	[2]		782,006	[2]
Long-term variable-rate loans | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	4,547,813	[2],[3]		4,718,162	[2],[3]
Long-term variable-rate loans | RTFC | Nonperforming Financing Receivable
Loans outstanding
Total loans outstanding	2,609			6,807
Long-term variable-rate loans | RTFC | Unadvanced commitments | Nonperforming Financing Receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		0	[3]
Loans guaranteed by RUS
Loans outstanding
Total loans outstanding	203,173	[2]		210,815	[2]
Loans guaranteed by RUS | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	0	[2],[3]		0	[2],[3]
Line of credit loans
Loans outstanding
Total loans outstanding	1,476,166	[2]		1,385,228	[2]
Line of credit loans | Unadvanced commitments
Unadvanced commitments
Total Unadvanced commitments	8,996,845	[2],[3]		8,704,586	[2],[3]
Line of credit loans | CFC | Nonperforming Financing Receivable
Loans outstanding
Total loans outstanding	5,000			5,000
Line of credit loans | CFC | Restructured financing receivable
Loans outstanding
Total loans outstanding	0	[4]		0	[4]
Line of credit loans | CFC | Unadvanced commitments | Nonperforming Financing Receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3]		0	[3]
Line of credit loans | CFC | Unadvanced commitments | Restructured financing receivable
Unadvanced commitments
Total Unadvanced commitments	0	[3],[4]		5,000	[3],[4]
Line of credit loans | NCSC | Nonperforming Financing Receivable
Loans outstanding
Total loans outstanding	450			0
Line of credit loans | NCSC | Unadvanced commitments | Nonperforming Financing Receivable
Unadvanced commitments
Total Unadvanced commitments	$ 0	[3]		$ 0	[3]

[1] Excludes deferred origination costs of $10 million at February 28, 2014 and May 31, 2013.

[2] Includes nonperforming and restructured loans.

[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.

[4] The unadvanced commitment is part of the terms outlined in the related restructure agreement. Loans advanced under these commitments would be classified as performing. Principal and interest due under these performing loans would be in addition to scheduled payments due under the restructured loan agreement.