Segment Reporting - Segment Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Segment Reporting Information [Line Items]
Revenues	$ 44,479,857	$ 40,599,286	$ 36,915,834
Cost of goods sold	42,706,205	38,588,143	35,512,988
Gross profit	1,773,652	2,011,143	1,402,846
Marketing, general and administrative	553,623	498,233	438,498
Operating earnings	1,220,029	1,512,910	964,348
Loss (gain) on investments	(182)	5,465	(126,729)
Interest, net	231,567	193,263	74,835
Equity income from investments	(97,350)	(102,389)	(131,414)
Income before income taxes	1,085,994	1,416,571	1,147,656
Intersegment Revenue	0	0	0
Goodwill	85,063	81,693	26,409
Capital expenditures	659,373	468,611	310,670
Depreciation and amortization	241,791	219,632	220,694
Total identifiable assets	13,504,270	13,645,024
Energy
Segment Reporting Information [Line Items]
Revenues	12,982,293	12,816,542
Cost of goods sold	11,846,458	11,514,463
Gross profit	1,135,835	1,302,079
Marketing, general and administrative	172,136	155,786
Operating earnings	963,699	1,146,293
Loss (gain) on investments	0	4,008
Interest, net	148,366	122,302
Equity income from investments	(1,357)	(7,537)
Income before income taxes	816,690	1,027,520
Intersegment Revenue	(481,465)	(467,583)
Goodwill	1,165	1,165	1,165
Capital expenditures	452,859	294,560	198,692
Depreciation and amortization	120,447	109,496	126,018
Total identifiable assets	4,409,594	3,704,796
Ag Business
Segment Reporting Information [Line Items]
Revenues	31,909,791	28,181,445	25,767,033
Cost of goods sold	31,341,453	27,544,040	25,204,301
Gross profit	568,338	637,405	562,732
Marketing, general and administrative	312,616	273,757	229,369
Operating earnings	255,722	363,648	333,363
Loss (gain) on investments	(27)	1,049	(118,344)
Interest, net	71,597	57,915	57,438
Equity income from investments	(15,194)	(22,737)	(40,482)
Income before income taxes	199,346	327,421	434,751
Goodwill	77,000	73,630	18,346
Capital expenditures	198,892	168,825	107,866
Depreciation and amortization	105,654	92,538	79,231
Total identifiable assets	6,146,547	7,316,410
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	69,238	68,882	64,809
Cost of goods sold	(241)	(2,777)	(2,611)
Gross profit	69,479	71,659	67,420
Marketing, general and administrative	68,871	68,690	66,421
Operating earnings	608	2,969	999
Loss (gain) on investments	(155)	408	(9,412)
Interest, net	11,604	13,046	11,568
Equity income from investments	(80,799)	(72,115)	(84,130)
Income before income taxes	69,958	61,630	82,973
Goodwill	6,898	6,898	6,898
Capital expenditures	7,622	5,226	4,112
Depreciation and amortization	15,690	17,598	15,445
Total identifiable assets	2,948,129	2,623,818
Reconciling Amounts
Segment Reporting Information [Line Items]
Revenues	(481,465)	(467,583)	(383,389)
Cost of goods sold	(481,465)	(467,583)	(383,389)
Gross profit	0	0	0
Marketing, general and administrative
Operating earnings	0	0	0
Income before income taxes	0	0	0
Intersegment Revenue	$ 481,465	$ 467,583	$ 383,389