Derivative Instruments and Hedging Activities - Fair Value of Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Jun. 30, 2014	[1]
Derivative assets:
Derivative asset, gross	$ 60.1	$ 33.8
Derivative liabilities:
Derivative liability, gross	(154.7)	(63.2)
Designated as Hedging Instrument
Derivative assets:
Derivative asset, gross	38.3	8.9
Derivative liabilities:
Derivative liability, gross	(2.1)	(36.5)
Designated as Hedging Instrument | Commodity Contracts
Derivative assets:
Derivative asset, gross	0.0	8.1
Derivative liabilities:
Derivative liability, gross	0.0	(4.2)
Designated as Hedging Instrument | Foreign Currency Contracts
Derivative assets:
Derivative asset, gross	29.1	0.8
Derivative liabilities:
Derivative liability, gross	(0.1)	(5.1)
Designated as Hedging Instrument | Cross Currency Contracts
Derivative assets:
Derivative asset, gross	8.2	0.0
Derivative liabilities:
Derivative liability, gross	0.0	(2.0)
Designated as Hedging Instrument | Interest Rate Contracts
Derivative assets:
Derivative asset, gross	1.0	0.0
Derivative liabilities:
Derivative liability, gross	(2.0)	(25.2)
Derivatives Subject To PGC and DS Mechanisms | Commodity Contracts
Derivative assets:
Derivative asset, gross	1.9	2.4
Derivative liabilities:
Derivative liability, gross	(4.8)	(0.8)
Derivatives Not Designated as Hedging Instruments | Commodity Contracts
Derivative assets:
Derivative asset, gross	19.9	22.5
Derivative liabilities:
Derivative liability, gross	$ (147.8)	$ (25.9)

[1] Certain immaterial amounts have been revised to correct the classification of derivatives.