Equities Changes in Equity (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
	Sep. 01, 2018	Feb. 28, 2019	Nov. 30, 2018	Feb. 28, 2018	Nov. 30, 2017	Feb. 28, 2019	Feb. 28, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 8,165,028	$ 8,292,092	$ 8,165,028	$ 7,742,948	$ 7,705,640	$ 8,165,028	$ 7,705,640
Reversal of prior year patronage and redemption estimates		81,681	24,072	1,060	1,561
Patronage Refunds		(74,980)		0
Redemptions of equities		(6,681)	(24,072)	(1,060)	(1,561)
Preferred stock dividends		(42,167)	(84,334)	(42,167)	(84,334)
Other, net		(1,654)	3,319	(1,942)	2,044
Net income (loss)		248,304	347,115	165,959	187,182	595,419	353,141
Net income (loss) attributable to CHS Inc.		248,766		166,007		596,270	353,653
Net income (loss) attributable to noncontrolling interests		(462)		(48)		(851)	(512)
Other comprehensive income (loss), net of tax		14,884	389	10,111	3,019	15,273	13,130
Estimated 2019 cash patronage refunds		(69,400)	(89,344)	3,823	(50,702)
Estimated 2019 equity redemptions		(39,850)	(50,081)	(12,375)	(19,901)
Ending Balance		8,402,229	8,292,092	7,866,357	7,742,948	8,402,229	7,866,357
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	3,837,580	3,789,158	3,837,580	3,885,139	3,906,426	3,837,580	3,906,426
Reversal of prior year patronage and redemption estimates		6,681	24,072	1,060	1,561
Patronage Refunds		0		0
Redemptions of equities		(5,988)	(22,004)	(953)	(1,449)
Other, net		(774)	(409)	(2,652)	(1,498)
Estimated 2019 equity redemptions		(39,850)	(50,081)	(12,375)	(19,901)
Ending Balance		3,749,227	3,789,158	3,870,219	3,885,139	3,749,227	3,870,219
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	29,498	29,315	29,498	29,717	29,836	29,498	29,836
Reversal of prior year patronage and redemption estimates		0	0	0	0
Patronage Refunds		0		0
Redemptions of equities		(74)	(183)	(16)	(53)
Other, net				(45)	(66)
Ending Balance		29,241	29,315	29,656	29,717	29,241	29,656
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	742,378	740,467	742,378	404,984	405,387	742,378	405,387
Reversal of prior year patronage and redemption estimates		(345,330)	0	(126,333)	0
Patronage Refunds		349,353		128,858
Redemptions of equities		(619)	(1,885)	(91)	(59)
Other, net		2,589	(26)	(1)	(344)
Ending Balance		746,460	740,467	407,417	404,984	746,460	407,417
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
Patronage Refunds		0		0
Redemptions of equities		0	0	0	0
Ending Balance		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	(199,915)	(204,232)	(199,915)	(177,341)	(180,360)	(199,915)	(180,360)
Patronage Refunds		0		0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(4,706)
Other comprehensive income (loss), net of tax		14,884	389	10,111	3,019
Ending Balance		(189,348)	(204,232)	(167,230)	(177,341)	(189,348)	(167,230)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,482,003	1,663,971	1,482,003	1,324,372	1,267,808	1,482,003	1,267,808
Reversal of prior year patronage and redemption estimates		420,330	0	126,333	0
Patronage Refunds		(424,333)		(128,858)
Preferred stock dividends		(42,167)	(84,334)	(42,167)	(84,334)
Other, net		(2,888)	3,436	816	3,954
Net income (loss) attributable to CHS Inc.		248,766	347,504	166,007	187,646
Estimated 2019 cash patronage refunds		(69,400)	(89,344)	3,823	(50,702)
Ending Balance		1,794,279	1,663,971	1,450,326	1,324,372	1,794,279	1,450,326
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	9,446	9,375	9,446	12,039	12,505	9,446	12,505
Patronage Refunds		0		0
Other, net		(581)	318	(60)	(2)
Net income (loss) attributable to noncontrolling interests		(462)	(389)	(48)	(464)
Ending Balance		$ 8,332	9,375	$ 11,931	$ 12,039	$ 8,332	$ 11,931
Accounting Standards Update 2016-01
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ (4,700)		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)
Accounting Standards Update 2016-01 | Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			$ 0