Retirement Benefits - Assumptions Used to Determine Benefit Obligations and Net Periodic Pension and Postretirement Benefit Costs (Detail)	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Compensation And Retirement Disclosure [Abstract]
Benefit obligation discount rates for pension plans, minimum	1.30%	2.00%	1.40%
Benefit obligation rates of compensation increase for pension plans, minimum	2.00%	2.00%	0.00%
Net periodic discount rates for pension plans, minimum	2.00%	1.40%	1.40%
Net periodic rates of compensation increase for pension plans, minimum	2.00%	2.00%	2.00%
Benefit obligation discount rates for pension plans, maximum	8.60%	8.30%	8.80%
Benefit obligation rates of compensation increase for pension plans, maximum	10.00%	10.00%	10.00%
Net periodic discount rates for pension plans, maximum	8.30%	8.80%	4.40%
Net periodic rates of compensation increase for pension plans, maximum	10.00%	10.00%	4.00%