Retirement Benefit Obligations - Schedule of Assumptions Used (Detail)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Postretirement Benefits
Weighted-average assumptions used to determine benefit obligations
Discount rate	2.50%	3.30%	4.00%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate for PBO	3.30%	4.00%	3.50%
Discount rate for Service Cost	3.60%	4.30%	3.90%
Discount rate for Interest on PBO	2.90%	3.60%	2.90%
Discount rate for Interest on Service Cost	3.30%	4.10%	3.50%
Domestic
Weighted-average assumptions used to determine benefit obligations
Discount rate	2.90%	3.60%	4.20%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate for PBO	3.60%	4.20%	3.80%
Discount rate for Service Cost	3.90%	4.30%	4.00%
Discount rate for Interest on PBO	3.20%	3.90%	3.30%
Discount rate for Interest on Service Cost	3.60%	4.30%	3.80%
Expected return on plan assets	6.00%	6.00%	6.50%
Foreign Pension Benefits
Weighted-average assumptions used to determine benefit obligations
Discount rate	1.70%	2.30%	2.80%
Rate of increase in future compensation	3.10%	3.40%	3.10%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate for PBO	2.30%	2.80%	2.70%
Discount rate for Service Cost	2.50%	3.70%	3.80%
Discount rate for Interest on PBO	2.00%	2.50%	2.40%
Discount rate for Interest on Service Cost	2.20%	3.30%	3.40%
Expected return on plan assets	4.20%	4.40%	4.70%
Rate of increase in future compensation	3.40%	3.10%	2.80%