Segment Reporting - Segment Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
May 31, 2021
May 31, 2020
May 31, 2021
May 31, 2020
Aug. 31, 2020
Segment Reporting Information [Line Items]          
Revenues $ 10,929,976 $ 7,241,031 $ 27,965,778 $ 21,460,742  
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax 10,929,976 7,241,031 27,965,778 21,460,742  
Operating earnings (loss) 127,925 37,920 75,577 310,617  
Interest Expense 28,992 26,661 82,897 95,043  
Other income (10,748) (8,076) (41,219) (32,926)  
Equity income from investments (146,522) (51,114) (260,654) (135,174)  
Income (loss) before income taxes 256,203 70,449 294,553 383,674  
Total assets 18,600,626   18,600,626   $ 15,993,947
Energy          
Segment Reporting Information [Line Items]          
Revenues, including intersegment revenues 1,815,077 960,352 4,643,387 4,550,155  
Revenues 1,704,798 890,919 4,334,803 4,247,392  
Intersegment Revenue (110,279) (69,433) (308,584) (302,763)  
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax 1,704,798 890,919 4,334,803 4,247,392  
Operating earnings (loss) 2,955 (56,792) (120,879) 241,594  
Interest Income, Operating (333)        
Interest Expense   (145) 492 43  
Other income (636) (614) (2,108) (2,516)  
Equity income from investments (1,035) (1,269) (2,355) (2,242)  
Income (loss) before income taxes 4,959 (54,764) (116,908) 246,309  
Total assets 4,451,203   4,451,203    
Ag          
Segment Reporting Information [Line Items]          
Revenues, including intersegment revenues 9,222,597 6,340,386 23,615,087 17,183,820  
Revenues 9,216,204 6,337,901 23,599,818 17,173,958  
Intersegment Revenue (6,393) (2,485) (15,269) (9,862)  
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax 9,216,204 6,337,901 23,599,818 17,173,958  
Operating earnings (loss) 134,606 95,328 212,223 88,102  
Interest Expense 17,661 16,261 48,796 57,761  
Other income (6,331) (8,294) (29,784) (31,142)  
Equity income from investments (16,855) (7,999) (43,974) 830  
Income (loss) before income taxes 140,131 95,360 237,185 60,653  
Total assets 8,388,074   8,388,074    
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) (8,799) (7,936) (24,661) (26,318)  
Interest Expense 10,318 10,176 33,721 34,277  
Other income (308) (355) (2,175) (2,272)  
Equity income from investments (65,444) (41,264) (118,477) (104,021)  
Income (loss) before income taxes 46,635 23,507 62,270 45,698  
Total assets 2,733,443   2,733,443    
Corporate and Other          
Segment Reporting Information [Line Items]          
Revenues, including intersegment revenues 10,842 13,515 38,370 43,514  
Revenues 8,974 12,211 31,157 39,392  
Intersegment Revenue (1,868) (1,304) (7,213) (4,122)  
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax 8,974 12,211 31,157 39,392  
Operating earnings (loss) (837) 7,320 8,894 7,239  
Interest Expense 390 1,810 1,536 8,680  
Other income (2,517) (254) (8,800) (2,714)  
Equity income from investments (63,188) (582) (95,848) (29,741)  
Income (loss) before income taxes 64,478 6,346 112,006 31,014  
Total assets 3,027,906   3,027,906    
Other Segments          
Segment Reporting Information [Line Items]          
Revenues (118,540) (73,222) (331,066) (316,747)  
Intersegment Revenue 118,540 73,222 331,066 316,747  
Revenue From Contract With Customer Net of Intersegment Revenue Excluding Assessed Tax 0     0  
Operating earnings (loss) 0 0 0 0  
Interest Expense 956 (1,441) (1,648) (5,718)  
Other income (956) 1,441 1,648 5,718  
Equity income from investments 0 0 0 0  
Income (loss) before income taxes $ 0 $ 0 $ 0 $ 0