Pension and Other Postretirement Benefits - Schedule of Weighted-average Asset Allocations by Asset Category (Details)	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	55.40%	57.50%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	44.20%	42.40%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocation	0.40%	0.10%