Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019	Aug. 31, 2019	Mar. 01, 2019
Segment Reporting Information [Line Items]
Remainingownershipacquired						75.00%
Revenues	$ 7,241,031	$ 8,497,941	$ 21,460,742	$ 23,465,769
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	7,241,031	8,497,941	21,460,742	23,465,769
Operating earnings (loss)	37,920	6,244	310,617	570,387
Interest Expense	26,661	42,773	95,043	122,950
Other (income) loss	(8,076)	(32,938)	(32,926)	(69,835)
Equity (income) loss from investments	(51,114)	(65,170)	(135,174)	(173,394)
Income (loss) before income taxes	70,449	61,579	383,674	690,666
Total assets	16,827,224		16,827,224		$ 16,447,494
Energy
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	960,352	1,841,290	4,550,155	5,722,338
Revenues	890,919	1,738,045	4,247,392	5,374,110
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	890,919	1,738,045	4,247,392	5,374,110
Operating earnings (loss)	(56,792)	572	241,594	537,932
Interest Expense	(145)	1,171	43	3,756
Other (income) loss	(614)	(1,098)	(2,516)	(4,301)
Equity (income) loss from investments	(1,269)	(760)	(2,242)	(1,828)
Income (loss) before income taxes	(54,764)	1,259	246,309	540,305
Total assets	4,545,401		4,545,401
Ag
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	6,340,386	6,749,182	17,183,820	18,056,033
Revenues	6,337,901	6,745,115	17,173,958	18,045,057
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	6,337,901	6,745,115	17,173,958	18,045,057
Operating earnings (loss)	95,328	12,090	88,102	45,088
Interest Expense	16,261	26,675	57,761	73,073
Other (income) loss	(8,294)	(31,685)	(31,142)	(64,341)
Equity (income) loss from investments	(7,999)	(4,012)	830	(2,675)
Income (loss) before income taxes	95,360	21,112	60,653	39,031
Total assets	6,742,438		6,742,438
Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	0	0	0	0
Operating earnings (loss)	(7,936)	(9,040)	(26,318)	(24,048)
Interest Expense	10,176	13,140	34,277	42,161
Other (income) loss	(355)	(399)	(2,272)	(2,362)
Equity (income) loss from investments	(41,264)	(41,959)	(104,021)	(118,416)
Income (loss) before income taxes	23,507	20,178	45,698	54,569
Total assets	2,743,305		2,743,305
Corporate and Other
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	13,515	16,418	43,514	52,179
Revenues	12,211	14,781	39,392	46,602
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	12,211	14,781	39,392	46,602
Operating earnings (loss)	7,320	2,622	7,239	11,415
Interest Expense	1,810	3,883	8,680	7,945
Other (income) loss	(254)	(1,852)	(2,714)	(2,816)
Equity (income) loss from investments	(582)	(18,439)	(29,741)	(50,475)
Income (loss) before income taxes	6,346	19,030	31,014	56,761
Total assets	2,796,080		2,796,080
Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	(73,222)	(108,949)	(316,747)	(364,781)
Operating earnings (loss)	0	0	0	0
Interest Expense	(1,441)	(2,096)	(5,718)	(3,985)
Other (income) loss	1,441	2,096	5,718	3,985
Equity (income) loss from investments	0	0	0	0
Income (loss) before income taxes	0	0	0	0
Total assets	0		0
Operating Segments [Member] | Energy
Segment Reporting Information [Line Items]
Intersegment Revenue	(69,433)	(103,245)	(302,763)	(348,228)
Operating Segments [Member] | Ag
Segment Reporting Information [Line Items]
Intersegment Revenue	(2,485)	(4,067)	(9,862)	(10,976)
Operating Segments [Member] | Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Intersegment Revenue	0	0	0	0
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Intersegment Revenue	(1,304)	(1,637)	(4,122)	(5,577)
Reconciling Amounts
Segment Reporting Information [Line Items]
Intersegment Revenue	$ 73,222	$ 108,949	$ 316,747	$ 364,781