Derivatives and Hedging Activities - Narrative (Details) lb in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2016 USD ($) lb	Mar. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) lb	Mar. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)
Fair value of derivatives
Total asset derivatives on a gross basis	$ 10.9		$ 10.9
Total liability derivatives on a gross basis	64.8		64.8
Cash collateral held by counterparties	$ 8.0		8.0		$ 0.0
Net derivative losses included in AOCI expected to be reclassified into earnings			$ (23.2)
Cash flow hedges | Commodity contracts
Fair value of derivatives
Amounts of raw materials to be purchased from forward contracts (in pounds) | lb	22.5		22.5
Cash flow hedges | Interest rate swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	$ 0.1	$ 0.1	$ 0.3	$ 0.3
Fair value hedging | Interest rate swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	0.6	$ 0.8	1.9	$ 2.1
Total notional amounts of interest rate contracts	$ 150.0		$ 150.0		$ 150.0