Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2019	May 31, 2018	Mar. 01, 2019	Aug. 31, 2018
Segment Reporting Information [Line Items]
remainingownershipacquired					75.00%
Revenues	$ 8,497,941	$ 9,087,328	$ 23,465,769	$ 24,099,365
Operating earnings (loss)	6,244	87,019	570,387	229,708
(Gain) loss on disposal of business	(2,474)	(124,050)	(3,886)	(131,755)
Interest Expense	42,773	49,340	122,950	130,218
Other (income) loss	(30,464)	(15,802)	(65,949)	(54,542)
Equity (income) loss from investments	(65,170)	(59,308)	(173,394)	(137,111)
Income (loss) before income taxes	61,579	236,839	690,666	422,898
Total assets	17,573,483		17,573,483			$ 16,381,178
Energy
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	1,841,290	1,999,628	5,722,338	5,845,437
Revenues	1,738,045		5,374,110
Operating earnings (loss)	572	29,729	537,932	179,077
(Gain) loss on disposal of business	0	(65,903)	0	(65,903)
Interest Expense	1,171	3,496	3,756	11,760
Other (income) loss	(1,098)	(967)	(4,301)	(2,977)
Equity (income) loss from investments	(760)	(967)	(1,828)	(2,779)
Income (loss) before income taxes	1,259	94,070	540,305	238,976
Total assets	4,573,463		4,573,463
Ag
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	6,749,182	7,193,316	18,056,033	18,574,846
Revenues	6,745,115		18,045,057
Operating earnings (loss)	12,090	63,170	45,088	70,954
(Gain) loss on disposal of business	(2,474)	5	(3,886)	(7,700)
Interest Expense	26,675	28,854	73,073	69,242
Other (income) loss	(29,211)	(14,430)	(60,455)	(47,128)
Equity (income) loss from investments	(4,012)	(11,359)	(2,675)	(25,180)
Income (loss) before income taxes	21,112	60,100	39,031	81,720
Total assets	7,377,779		7,377,779
Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	0	0	0	0
Operating earnings (loss)	(9,040)	(4,153)	(24,048)	(14,527)
(Gain) loss on disposal of business	0	0	0	0
Interest Expense	13,140	13,119	42,161	39,067
Other (income) loss	(399)	(441)	(2,362)	(2,612)
Equity (income) loss from investments	(41,959)	(35,639)	(118,416)	(79,986)
Income (loss) before income taxes	20,178	18,808	54,569	29,004
Total assets	2,788,010		2,788,010
Corporate and Other
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	16,418	14,075	52,179	46,018
Revenues	14,781		46,602
Operating earnings (loss)	2,622	(1,727)	11,415	(5,796)
(Gain) loss on disposal of business	0	(58,152)	0	(58,152)
Interest Expense	3,883	4,324	7,945	11,569
Other (income) loss	(1,852)	(417)	(2,816)	(3,245)
Equity (income) loss from investments	(18,439)	(11,343)	(50,475)	(29,166)
Income (loss) before income taxes	19,030	63,861	56,761	73,198
Total assets	2,834,231		2,834,231
Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	(108,949)	(119,691)	(364,781)	(366,936)
Operating earnings (loss)	0		0	0
(Gain) loss on disposal of business	0		0
Interest Expense	(2,096)	(453)	(3,985)	(1,420)
Other (income) loss	2,096	453	3,985	1,420
Equity (income) loss from investments	0	0	0	0
Income (loss) before income taxes	0	0	0	0
Total assets	0		0
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations [Member] | Energy
Segment Reporting Information [Line Items]
Revenues	(103,245)	(114,497)	(348,228)	(349,361)
Intersegment Eliminations [Member] | Ag
Segment Reporting Information [Line Items]
Revenues	(4,067)	(3,784)	(10,976)	(11,391)
Intersegment Eliminations [Member] | Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations [Member] | Corporate and Other
Segment Reporting Information [Line Items]
Revenues	(1,637)	(1,410)	(5,577)	(6,184)
Intersegment Eliminations [Member] | Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	$ 108,949	119,691	$ 364,781	366,936
Reconciling Amounts
Segment Reporting Information [Line Items]
(Gain) loss on disposal of business		$ 0		$ 0