Equities Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	May 31, 2020	Feb. 29, 2020	Nov. 30, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	May 31, 2020	May 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 8,623,956	$ 8,622,916	$ 8,617,530	$ 8,402,229	$ 8,292,092	$ 8,165,028	$ 8,617,530	$ 8,165,028
Reversal of prior year patronage and redemption estimates	77,438	93,387	5,447	45,815	81,681	24,072
patronage refund	(82)	(90,030)		(689)	(74,980)
Redemptions of equities	(77,438)	(3,387)	(5,447)	(45,644)	(6,681)	(24,072)
Preferred stock dividends		(42,167)	(84,334)		(42,167)	(84,334)
ASC Topic 842 cumulative-effect adjustment			(33,707)
Other, net	(606)	(512)	(949)	(470)	(1,654)	3,319
Net income (loss)	97,501	125,694	178,737	54,713	248,304	347,115	401,932	650,132
Net income (loss) attributable to CHS Inc.	97,648			54,620			400,977	650,890
Net income (loss) attributable to noncontrolling interests	(147)			93			955	(758)
Other comprehensive income (loss), net of tax	(2,009)	(10,585)	(1,638)	(22,313)	14,884	389	(14,232)	(7,040)
Estimated 2019 cash patronage refunds	13,551	(22,206)	(28,504)	(15,494)	(69,400)	(89,344)
Estimated 2019 equity redemptions	47,975	(49,154)	(91,633)	(6,438)	(39,850)	(50,081)
Ending Balance	8,780,286	8,623,956	8,622,916	8,411,709	8,402,229	8,292,092	8,780,286	8,411,709
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	3,613,612	3,662,578	3,753,493	3,749,227	3,789,158	3,837,580	3,753,493	3,837,580
Reversal of prior year patronage and redemption estimates	67,438	3,387	5,447	45,815	6,681	24,072
Redemptions of equities	(64,273)	(2,998)	(4,721)	(34,798)	(5,988)	(22,004)
Other, net	(1,544)	(201)	(8)	(1,285)	(774)	(409)
Estimated 2019 equity redemptions	47,975	(49,154)	(91,633)	(6,438)	(39,850)	(50,081)
Ending Balance	3,663,208	3,613,612	3,662,578	3,752,521	3,749,227	3,789,158	3,663,208	3,752,521
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	29,000	29,020	29,074	29,241	29,315	29,498	29,074	29,498
Reversal of prior year patronage and redemption estimates	0	0	0	0	0	0
Redemptions of equities	(91)	(20)	(54)	(34)	(74)	(183)
Other, net	(7)
Ending Balance	28,902	29,000	29,020	29,207	29,241	29,315	28,902	29,207
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,206,901	1,205,599	1,206,310	746,460	740,467	742,378	1,206,310	742,378
Reversal of prior year patronage and redemption estimates	10,000	(472,398)	0		(345,330)	0
patronage refund	327	474,066		3,212	349,353
Redemptions of equities	(13,074)	(369)	(672)	(10,812)	(619)	(1,885)
Other, net	(116)	3	(39)	(3,722)	2,589	(26)
Ending Balance	1,204,038	1,206,901	1,205,599	735,138	746,460	740,467	1,204,038	735,138
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038
Redemptions of equities	0	0	0	0	0	0
Ending Balance	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038	2,264,038
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(239,156)	(228,571)	(226,933)	(189,348)	(204,232)	(199,915)	(226,933)	(199,915)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax						(4,706)
Other comprehensive income (loss), net of tax	(2,009)	(10,585)	(1,638)	(22,313)	14,884	389
Ending Balance	(241,165)	(239,156)	(228,571)	(211,661)	(189,348)	(204,232)	(241,165)	(211,661)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,740,983	1,681,597	1,584,158	1,794,279	1,663,971	1,482,003	1,584,158	1,482,003
Reversal of prior year patronage and redemption estimates	0	562,398	0		420,330	0
patronage refund	(409)	(564,096)		(3,901)	(424,333)
Preferred stock dividends		(42,167)	(84,334)		(42,167)	(84,334)
Other, net	1,053	10	(1,312)	4,526	(2,888)	3,436
Net income (loss) attributable to CHS Inc.	97,648	125,447	177,882	54,620	248,766	347,504
Estimated 2019 cash patronage refunds	13,551	(22,206)	(28,504)	(15,494)	(69,400)	(89,344)
Ending Balance	1,852,826	1,740,983	1,681,597	1,834,030	1,794,279	1,663,971	1,852,826	1,834,030
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	8,578	8,655	7,390	8,332	9,375	9,446	7,390	9,446
Other, net	8	(324)	410	11	(581)	318
Net income (loss) attributable to noncontrolling interests	(147)	247	855	93	(462)	(389)
Ending Balance	$ 8,439	$ 8,578	8,655	$ 8,436	$ 8,332	9,375	$ 8,439	$ 8,436
Accounting Standards Update 2016-02 [Member] | Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			0
Accounting Standards Update 2016-02 [Member] | Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			0
Accounting Standards Update 2016-02 [Member] | Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			0
Accounting Standards Update 2016-02 [Member] | Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			0
Accounting Standards Update 2016-02 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			0
Accounting Standards Update 2016-02 [Member] | Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			(33,707)
Accounting Standards Update 2016-02 [Member] | Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
ASC Topic 842 cumulative-effect adjustment			$ 0
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax						4,706
Accounting Standards Update 2016-01 | Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax						$ (4,706)