Financial Instruments and Risk Management (Details 2) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Fair Value Measurements
Total current derivative contracts, assets	$ 20.0	$ 9.4
Long-term derivative assets	85.6	3.1
Total current derivative contracts, liabilities	32.9	12.3
Total noncurrent derivative contracts, liabilities	$ 8.0	7.6
Discount factor	12 month LIBOR
Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	$ 9.1	5.1
Long-term derivative assets	2.6	2.7
Total current derivative contracts, liabilities	20.4	8.5
Total noncurrent derivative contracts, liabilities	7.2	7.3
Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	10.9	4.3
Long-term derivative assets	75.1
Total current derivative contracts, liabilities	9.8	2.9
Interest rate and other contracts
Fair Value Measurements
Long-term derivative assets	7.9	0.4
Total current derivative contracts, liabilities	2.7	0.9
Total noncurrent derivative contracts, liabilities	0.8	0.3
Derivatives Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	6.9	4.6
Long-term derivative assets	1.6	2.6
Total current derivative contracts, liabilities	23.5	9.0
Total noncurrent derivative contracts, liabilities	6.1	7.1
Derivatives Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	6.5	3.8
Long-term derivative assets	1.5	2.2
Total current derivative contracts, liabilities	16.2	6.9
Total noncurrent derivative contracts, liabilities	5.8	6.8
Derivatives Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	0.4	0.8
Total current derivative contracts, liabilities	6.8	1.6
Derivatives Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Long-term derivative assets	0.1	0.4
Total current derivative contracts, liabilities	0.5	0.5
Total noncurrent derivative contracts, liabilities	0.3	0.3
Derivatives Not Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	13.1	4.8
Long-term derivative assets	84.0	0.5
Total current derivative contracts, liabilities	9.4	3.3
Total noncurrent derivative contracts, liabilities	1.9	0.5
Derivatives Not Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	2.6	1.3
Long-term derivative assets	1.1	0.5
Total current derivative contracts, liabilities	4.2	1.6
Total noncurrent derivative contracts, liabilities	1.4	0.5
Derivatives Not Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	10.5	3.5
Long-term derivative assets	75.1
Total current derivative contracts, liabilities	3.0	1.3
Derivatives Not Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Long-term derivative assets	7.8
Total current derivative contracts, liabilities	2.2	$ 0.4
Total noncurrent derivative contracts, liabilities	$ 0.5