Postretirement and Other Employee Benefits (Weighted-Average Actuarial Assumptions) (Details)	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Net periodic benefit cost:
Expected long-term return on plan assets	3.60%	3.80%	3.30%
Rate of compensation increase	4.40%	3.30%	2.70%
Discount rate	2.20%	2.10%	1.90%
Projected benefit obligation:
Expected long-term return on plan assets	2.00%	3.60%	4.00%
Rate of compensation increase	4.30%	4.40%	4.40%
Discount rate	1.70%	2.20%	2.30%