Segment Reporting - Segment Information (Details) - USD ($)	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 31,900,453,000	$ 32,683,347,000	$ 32,037,426,000
Revenues, including intersegment revenues	31,900,453,000
Operating earnings (loss)	659,602,000	452,364,000	(173,878,000)
(Gain/recovery) loss on disposal of business	(3,886,000)	(131,816,000)	2,190,000
Interest expense	167,065,000	149,202,000	171,239,000
Other (income) loss	(82,423,000)	(82,737,000)	(99,803,000)
Equity (income) loss from investments	(236,755,000)	(153,515,000)	(137,338,000)
Income (loss) before income taxes	815,601,000	671,230,000	(110,166,000)
Intersegment revenues	0	0	0
Capital expenditures	443,216,000	355,412,000	444,397,000
Depreciation and amortization	473,211,000	478,050,000	480,223,000
Total assets	16,447,494,000	16,381,178,000
Reconciling Amounts
Segment Reporting Information [Line Items]
(Gain/recovery) loss on disposal of business			0
Energy
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	7,119,076,000
(Gain/recovery) loss on disposal of business			0
Ag
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	24,720,072,000
(Gain/recovery) loss on disposal of business			2,190,000
Corporate and Other
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	61,305,000
(Gain/recovery) loss on disposal of business			0
Operating Segments | Energy
Segment Reporting Information [Line Items]
Revenues	7,581,450,000	8,068,717,000	6,620,680,000
Operating earnings (loss)	615,662,000	388,112,000	75,203,000
(Gain/recovery) loss on disposal of business	0	(65,862,000)
Interest expense	5,719,000	14,627,000	18,365,000
Other (income) loss	(5,548,000)	(9,698,000)	(1,099,000)
Equity (income) loss from investments	(2,697,000)	(3,063,000)	(3,181,000)
Income (loss) before income taxes	618,188,000	452,108,000	61,118,000
Intersegment revenues	(462,374,000)	(479,598,000)	(392,842,000)
Capital expenditures	268,877,000	248,207,000	260,543,000
Depreciation and amortization	233,624,000	230,230,000	223,229,000
Total assets	4,401,793,000	4,168,239,000
Operating Segments | Ag
Segment Reporting Information [Line Items]
Revenues	24,736,425,000	25,052,395,000	25,738,740,000
Operating earnings (loss)	65,181,000	93,728,000	(268,884,000)
(Gain/recovery) loss on disposal of business	(3,886,000)	(7,707,000)
Interest expense	101,386,000	94,256,000	71,986,000
Other (income) loss	(70,888,000)	(68,471,000)	(65,622,000)
Equity (income) loss from investments	(4,447,000)	1,392,000	(7,277,000)
Income (loss) before income taxes	43,016,000	74,258,000	(270,161,000)
Intersegment revenues	(16,353,000)	(14,914,000)	(20,312,000)
Capital expenditures	110,197,000	77,962,000	146,139,000
Depreciation and amortization	208,294,000	218,716,000	232,443,000
Total assets	6,415,580,000	6,534,777,000
Operating Segments | Nitrogen Production
Segment Reporting Information [Line Items]
Revenues	0	0	0
Operating earnings (loss)	(35,046,000)	(20,619,000)	(18,430,000)
(Gain/recovery) loss on disposal of business	0	0	0
Interest expense	55,226,000	50,499,000	48,893,000
Other (income) loss	(2,769,000)	(3,061,000)	(30,534,000)
Equity (income) loss from investments	(160,373,000)	(106,895,000)	(66,530,000)
Income (loss) before income taxes	72,870,000	38,838,000	29,741,000
Intersegment revenues	0	0	0
Capital expenditures	0	0	0
Depreciation and amortization	0	0	0
Total assets	2,730,306,000	2,758,668,000
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	68,710,000	64,516,000	95,414,000
Operating earnings (loss)	13,805,000	(8,857,000)	38,233,000
(Gain/recovery) loss on disposal of business	0	(58,247,000)
Interest expense	11,684,000	(7,712,000)	33,250,000
Other (income) loss	(10,168,000)	(3,975,000)	(3,803,000)
Equity (income) loss from investments	(69,238,000)	(44,949,000)	(60,350,000)
Income (loss) before income taxes	81,527,000	106,026,000	69,136,000
Intersegment revenues	(7,405,000)	(7,769,000)	(4,254,000)
Capital expenditures	64,142,000	29,243,000	37,715,000
Depreciation and amortization	31,293,000	29,104,000	24,551,000
Total assets	2,899,815,000	2,919,494,000
Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	(486,132,000)	(502,281,000)	(417,408,000)
Operating earnings (loss)	0	0	0
(Gain/recovery) loss on disposal of business	0	0
Interest expense	(6,950,000)	(2,468,000)	(1,255,000)
Other (income) loss	6,950,000	2,468,000	1,255,000
Equity (income) loss from investments	0	0	0
Income (loss) before income taxes	0	0	0
Intersegment revenues	486,132,000	502,281,000	417,408,000
Capital expenditures	0	0	0
Depreciation and amortization	0	0	$ 0
Total assets	$ 0	$ 0