CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 58.7	$ 132.8	$ 146.5
Other comprehensive (loss) income, net of tax
Pension and postretirement benefits (loss) gain, net of tax of $12.0, $(22.1) and $(48.3), respectively	(20.1)	36.9	80.5
Net (loss) gain on derivative instruments, net of tax of $21.7, $(29.5) and $5.3, respectively	(36.1)	49.1	(8.7)
Unrealized gain on marketable securities, net of tax of $0.0, $0.0 and $(0.2), respectively	0.1	0.0	0.3
Foreign currency translation	(26.9)	4.5	5.0
Other comprehensive (loss) income, net of tax	(83.0)	90.5	77.1
Comprehensive (loss) income, net of tax	(24.3)	223.3	223.6
Less: Comprehensive income attributable to the noncontrolling interest	0.0	0.0	0.7
Comprehensive (loss) income attributable to Carpenter	$ (24.3)	$ 223.3	$ 222.9