Segment Reporting - Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 30,347,203	$ 34,582,442	$ 42,664,033
Operating earnings	310,196	715,412	1,049,948
(Gain) loss on investments	(9,252)	(5,239)	(114,162)
Interest expense, net	75,347	60,333	140,253
Equity (income) loss from investments	(175,777)	(107,850)	(107,446)
Income before income taxes	419,878	768,168	1,131,303
Related party sales	0	0	0
Capital expenditures	692,780	1,186,790	919,076
Depreciation and amortization	447,492	355,422	306,247
Total assets	17,317,709	15,228,312
Energy [Member]
Segment Reporting Information [Line Items]
Revenues	5,789,307	8,694,326	12,181,212
Operating earnings	248,173	523,451	793,924
(Gain) loss on investments	0	0	0
Interest expense, net	(22,531)	(12,350)	69,522
Equity (income) loss from investments	(4,739)	(2,330)	(4,014)
Income before income taxes	275,443	538,131	728,416
Related party sales	(341,765)	(483,989)	(600,433)
Capital expenditures	376,841	696,825	539,170
Depreciation and amortization	193,525	148,292	137,408
Total assets	4,306,297	4,624,471
Ag [Member]
Segment Reporting Information [Line Items]
Revenues	24,849,634	26,311,350	31,022,507
Operating earnings	52,334	190,860	249,944
(Gain) loss on investments	(6,157)	(2,875)	(1,949)
Interest expense, net	35,199	56,380	60,742
Equity (income) loss from investments	(7,644)	(12,293)	(22,279)
Income before income taxes	30,936	149,648	213,430
Related party sales	(40,336)	(11,403)	(9,960)
Capital expenditures	260,865	417,950	329,613
Depreciation and amortization	230,172	192,438	157,102
Total assets	7,002,916	7,814,689
Nitrogen Production [Member]
Segment Reporting Information [Line Items]
Revenues	0
Operating earnings	(6,193)
(Gain) loss on investments	0
Interest expense, net	34,437
Equity (income) loss from investments	(74,700)
Income before income taxes	34,070
Related party sales	0
Capital expenditures	0
Depreciation and amortization	0
Total assets	2,796,323
Foods [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0
Operating earnings	(7,719)	(1,454)	(1,292)
(Gain) loss on investments	0	0	0
Interest expense, net	2,692	3,854	5,419
Equity (income) loss from investments	(75,175)	(67,955)	(55,104)
Income before income taxes	64,764	62,647	48,393
Related party sales	0	0	0
Capital expenditures	0	0	0
Depreciation and amortization	0	0	0
Total assets	369,487	347,748
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues	92,725	74,828	73,827
Operating earnings	23,601	2,555	7,372
(Gain) loss on investments	(3,095)	(2,364)	(112,213)
Interest expense, net	25,550	12,449	4,570
Equity (income) loss from investments	(13,519)	(25,272)	(26,049)
Income before income taxes	14,665	17,742	141,064
Related party sales	(2,362)	(2,670)	(3,120)
Capital expenditures	55,074	72,015	50,293
Depreciation and amortization	23,795	14,692	11,737
Total assets	2,842,686	2,441,404
Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	(384,463)	(498,062)	(613,513)
Operating earnings	0	0	0
(Gain) loss on investments	0	0	0
Interest expense, net	0	0	0
Equity (income) loss from investments	0	0	0
Income before income taxes	0	0	0
Related party sales	384,463	498,062	613,513
Capital expenditures	0	0	0
Depreciation and amortization	0	0	$ 0
Total assets	$ 0	$ 0