Equities - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ 9,017,326	$ 8,819,173	$ 8,617,530
Other comprehensive loss, net of tax	(38,944)	17,533	(6,991)
Balance	9,461,266	9,017,326	8,819,173
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(52,163)	4,048	(4,751)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	22,240	20,256	19,908
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(141,385)	(159,680)	(172,478)
Other Comprehensive Income (Loss), before Tax	(29,923)	24,304	15,157
Tax effect	2,668	(6,009)	(2,359)
Other comprehensive loss, net of tax	(27,255)	18,295	12,798
Balance	(168,640)	(141,385)	(159,680)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(2,161)	11,700	16,430
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	7,455	(19,753)	(22,291)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	4,824	10,886	15,297
Other Comprehensive Income (Loss), before Tax	5,294	(8,053)	(5,861)
Tax effect	(1,275)	1,991	1,450
Other comprehensive loss, net of tax	4,019	(6,062)	(4,411)
Balance	8,843	4,824	10,886
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(15,809)	5,573	(17,021)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0	0
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(79,830)	(85,130)	(69,752)
Other Comprehensive Income (Loss), before Tax	(15,809)	5,573	(17,021)
Tax effect	101	(273)	1,643
Other comprehensive loss, net of tax	(15,708)	5,300	(15,378)
Balance	(95,538)	(79,830)	(85,130)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(70,133)	21,321	(5,342)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	29,695	503	(2,383)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(216,391)	(233,924)	(226,933)
Other Comprehensive Income (Loss), before Tax	(40,438)	21,824	(7,725)
Tax effect	1,494	(4,291)	734
Other comprehensive loss, net of tax	(38,944)	17,533	(6,991)
Balance	$ (255,335)	$ (216,391)	$ (233,924)