Equities Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 8,617,530	$ 8,165,028
Reversal of prior year patronage and redemption estimates	5,447	24,072
Redemptions of equities	(5,447)	(24,072)
Preferred stock dividends	(84,334)	(84,334)
ASC Topic 842 cumulative-effect adjustment	(33,707)
Other, net	(949)	3,319
Net income (loss)	178,737	347,115
Net income (loss) attributable to CHS Inc.	177,882	347,504
Net income (loss) attributable to noncontrolling interests	855	(389)
Other comprehensive income (loss), net of tax	(1,638)	389
Estimated 2019 cash patronage refunds	(28,504)	(89,344)
Estimated 2019 equity redemptions	(91,633)	(50,081)
Ending Balance	8,622,916	8,292,092
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	3,753,493	3,837,580
Reversal of prior year patronage and redemption estimates	5,447	24,072
Redemptions of equities	(4,721)	(22,004)
Other, net	(8)	(409)
Estimated 2019 equity redemptions	(91,633)	(50,081)
Ending Balance	3,662,578	3,789,158
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	29,074	29,498
Reversal of prior year patronage and redemption estimates	0	0
Redemptions of equities	(54)	(183)
Ending Balance	29,020	29,315
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,206,310	742,378
Reversal of prior year patronage and redemption estimates	0	0
Redemptions of equities	(672)	(1,885)
Other, net	(39)	(26)
Ending Balance	1,205,599	740,467
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	2,264,038	2,264,038
Redemptions of equities	0	0
Ending Balance	2,264,038	2,264,038
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(226,933)	(199,915)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(4,706)
Other comprehensive income (loss), net of tax	(1,638)	389
Ending Balance	(228,571)	(204,232)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,584,158	1,482,003
Reversal of prior year patronage and redemption estimates	0	0
Preferred stock dividends	(84,334)	(84,334)
Other, net	(1,312)	3,436
Net income (loss) attributable to CHS Inc.	177,882	347,504
Estimated 2019 cash patronage refunds	(28,504)	(89,344)
Ending Balance	1,681,597	1,663,971
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	7,390	9,446
Other, net	410	318
Net income (loss) attributable to noncontrolling interests	855	(389)
Ending Balance	8,655	9,375
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)