Derivatives and Hedging Activities - Narrative (Details) lb in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2015 USD ($) lb	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) lb	Dec. 31, 2014 USD ($)	Jun. 30, 2015 USD ($)
Fair value of derivatives
Total asset derivatives on a gross basis	$ 8.6		$ 8.6
Total liability derivatives on a gross basis	75.1		75.1
Cash collateral held by counterparties	$ 0.7		0.7		$ 0.0
Net derivative losses included in AOCI expected to be reclassified into earnings			$ (26.6)
Cash flow hedges | Commodity contracts
Fair value of derivatives
Amounts of raw materials to be purchased from forward contracts | lb	25.0		25.0
Cash flow hedges | Interest rate swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	$ 0.1	$ 0.1	$ 0.2	$ 0.2
Fair value hedging | Interest rate swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	0.6	$ 0.9	1.3	$ 1.2
Total notional amounts of interest rate contracts	$ 150.0		$ 150.0		$ 150.0