Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020	Aug. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 8,320,159	$ 6,598,226	$ 17,035,802	$ 14,219,711
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	8,320,159	6,598,226	17,035,802	14,219,711
Operating earnings (loss)	(59,790)	115,485	(52,347)	272,697
Interest Expense	28,855	33,411	53,905	68,382
Other income	(17,846)	(11,352)	(30,470)	(24,850)
Equity income from investments	(64,109)	(34,398)	(114,132)	(84,060)
Income (loss) before income taxes	(6,690)	127,824	38,350	313,225
Total assets	18,566,143		18,566,143		$ 15,993,947
Energy
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	1,470,465	1,561,908	2,828,310	3,589,803
Revenues	1,372,158	1,461,050	2,630,005	3,356,473
Intersegment Revenue	(98,307)	(100,858)	(198,305)	(233,330)
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	1,372,158	1,461,050	2,630,005	3,356,473
Operating earnings (loss)	(55,449)	137,187	(123,834)	298,386
Interest Income, Operating	1,063
Interest Expense		(187)	826	187
Other income	(990)	(938)	(1,472)	(1,902)
Equity income from investments	(832)	(609)	(1,321)	(973)
Income (loss) before income taxes	(54,690)	138,921	(121,867)	301,074
Total assets	4,415,250		4,415,250
Ag
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	6,942,185	5,127,441	14,392,490	10,843,434
Revenues	6,938,212	5,124,202	14,383,614	10,836,057
Intersegment Revenue	(3,973)	(3,239)	(8,876)	(7,377)
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	6,938,212	5,124,202	14,383,614	10,836,057
Operating earnings (loss)	2,093	(6,809)	77,617	(7,226)
Interest Expense	16,630	20,759	31,135	41,500
Other income	(11,636)	(11,395)	(23,453)	(22,848)
Equity income from investments	(16,945)	4,672	(27,118)	8,829
Income (loss) before income taxes	14,044	(20,845)	97,053	(34,707)
Total assets	8,687,820		8,687,820
Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	0	0	0	0
Intersegment Revenue	0	0	0	0
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	0			0
Operating earnings (loss)	(8,240)	(10,559)	(15,862)	(18,381)
Interest Expense	12,241	11,971	23,403	24,101
Other income	(302)	(348)	(1,867)	(1,916)
Equity income from investments	(31,344)	(27,923)	(53,033)	(62,757)
Income (loss) before income taxes	11,165	5,741	15,635	22,191
Total assets	2,667,517		2,667,517
Corporate and Other
Segment Reporting Information [Line Items]
Revenues, including intersegment revenues	12,046	14,049	27,528	29,999
Revenues	9,789	12,974	22,183	27,181
Intersegment Revenue	(2,257)	(1,075)	(5,345)	(2,818)
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	9,789	12,974	22,183	27,181
Operating earnings (loss)	1,806	(4,334)	9,732	(82)
Interest Expense	7	3,032	1,145	6,870
Other income	(6,004)	(835)	(6,282)	(2,460)
Equity income from investments	(14,988)	(10,538)	(32,660)	(29,159)
Income (loss) before income taxes	22,791	4,007	47,529	24,667
Total assets	2,795,556		2,795,556
Other Segments
Segment Reporting Information [Line Items]
Revenues	(104,537)	(105,172)	(212,526)	(243,525)
Intersegment Revenue	104,537	105,172	212,526	243,525
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax	0			0
Operating earnings (loss)	0	0	0	0
Interest Expense	(1,086)	(2,164)	(2,604)	(4,276)
Other income	1,086	2,164	2,604	4,276
Equity income from investments	0	0	0	0
Income (loss) before income taxes	$ 0	$ 0	$ 0	$ 0