Financial Instruments and Risk Management (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements
Total current derivative contracts, assets	$ 20.4	$ 9.4
Total noncurrent derivative contracts, assets	3.3	3.1
Total current derivative contracts, liabilities	50.5	12.3
Total noncurrent derivative contracts, liabilities	$ 31.3	7.6
Discount factor	12-month LIBOR
Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	$ 10.0	5.1
Total noncurrent derivative contracts, assets	1.0	2.7
Total current derivative contracts, liabilities	16.9	8.5
Total noncurrent derivative contracts, liabilities	7.9	7.3
Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	7.5	4.3
Total noncurrent derivative contracts, assets	0.2
Total current derivative contracts, liabilities	33.0	2.9
Other contracts
Fair Value Measurements
Total current derivative contracts, assets	2.9
Interest rate and other contracts
Fair Value Measurements
Total current derivative contracts, liabilities	0.6	0.9
Interest rate contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	2.1	0.4
Total noncurrent derivative contracts, liabilities	23.4	0.3
Derivatives Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	7.9	4.6
Total noncurrent derivative contracts, assets	1.2	2.6
Total current derivative contracts, liabilities	12.4	9.0
Total noncurrent derivative contracts, liabilities	8.0	7.1
Derivatives Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	6.0	3.8
Total noncurrent derivative contracts, assets	1.0	2.2
Total current derivative contracts, liabilities	11.8	6.9
Total noncurrent derivative contracts, liabilities	7.9	6.8
Derivatives Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	1.9	0.8
Total noncurrent derivative contracts, assets	0.2
Total current derivative contracts, liabilities		1.6
Derivatives Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Total current derivative contracts, liabilities	0.6	0.5
Derivatives Designated As Hedging Instruments | Interest rate contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets		0.4
Total noncurrent derivative contracts, liabilities	0.1	0.3
Derivatives Not Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	12.5	4.8
Total noncurrent derivative contracts, assets	2.1	0.5
Total current derivative contracts, liabilities	38.1	3.3
Total noncurrent derivative contracts, liabilities	23.3	0.5
Derivatives Not Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	4.0	1.3
Total noncurrent derivative contracts, assets		0.5
Total current derivative contracts, liabilities	5.1	1.6
Total noncurrent derivative contracts, liabilities		0.5
Derivatives Not Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	5.6	3.5
Total current derivative contracts, liabilities	33.0	1.3
Derivatives Not Designated As Hedging Instruments | Other contracts
Fair Value Measurements
Total current derivative contracts, assets	2.9
Derivatives Not Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Total current derivative contracts, liabilities		$ 0.4
Derivatives Not Designated As Hedging Instruments | Interest rate contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	2.1
Total noncurrent derivative contracts, liabilities	$ 23.3