Equities - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ 9,461,266	$ 9,017,326	$ 8,819,173
Other comprehensive income, net of tax	(10,060)	(38,944)	17,533
Balance	10,452,389	9,461,266	9,017,326
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(13,596)	(52,163)	4,048
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	93	22,240	20,256
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(168,640)	(141,385)	(159,680)
Other Comprehensive Income (Loss), before Tax	(13,503)	(29,923)	24,304
Tax effect	8,218	2,668	(6,009)
Other comprehensive income, net of tax	(5,285)	(27,255)	18,295
Balance	(173,925)	(168,640)	(141,385)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(25,024)	(2,161)	11,700
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	16,044	7,455	(19,753)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	8,843	4,824	10,886
Other Comprehensive Income (Loss), before Tax	(8,980)	5,294	(8,053)
Tax effect	2,169	(1,275)	1,991
Other comprehensive income, net of tax	(6,811)	4,019	(6,062)
Balance	2,032	8,843	4,824
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	1,829	(15,809)	5,573
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	(95,538)	(79,830)	(85,130)
Other Comprehensive Income (Loss), before Tax	1,829	(15,809)	5,573
Tax effect	207	101	(273)
Other comprehensive income, net of tax	2,036	(15,708)	5,300
Balance	(93,502)	(95,538)	(79,830)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(36,791)	(70,133)	21,321
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	16,137	29,695	503
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(255,335)	(216,391)	(233,924)
Other Comprehensive Income (Loss), before Tax	(20,654)	(40,438)	21,824
Tax effect	10,594	1,494	(4,291)
Other comprehensive income, net of tax	(10,060)	(38,944)	17,533
Balance	$ (265,395)	$ (255,335)	$ (216,391)