Financial Instruments and Risk Management (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value Measurements
Total current derivative contracts, assets	$ 12.1	$ 7.1
Total noncurrent derivative contracts, assets	0.6	0.1
Total current derivative contracts, liabilities	28.8	29.6
Total noncurrent derivative contracts, liabilities	21.9	20.3
Discount factor	12-month LIBOR
Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	7.5	4.3
Total noncurrent derivative contracts, assets	0.1
Total current derivative contracts, liabilities	19.2	21.2
Total noncurrent derivative contracts, liabilities	21.7	20.3
Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	3.7	1.7
Total noncurrent derivative contracts, assets		0.1
Total current derivative contracts, liabilities	8.9	7.6
Other contracts
Fair Value Measurements
Total current derivative contracts, assets	0.9	1.1
Interest rate contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	0.5
Total noncurrent derivative contracts, liabilities	0.2
Interest rate and other contracts
Fair Value Measurements
Total current derivative contracts, liabilities	0.7	0.8
Derivatives Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	7.0	2.8
Total noncurrent derivative contracts, assets	0.6
Total current derivative contracts, liabilities	20.1	21.5
Total noncurrent derivative contracts, liabilities	21.9	20.3
Derivatives Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	6.2	2.6
Total noncurrent derivative contracts, assets	0.1
Total current derivative contracts, liabilities	17.6	19.2
Total noncurrent derivative contracts, liabilities	21.7	20.3
Derivatives Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	0.8	0.2
Total current derivative contracts, liabilities	1.8	1.5
Derivatives Designated As Hedging Instruments | Interest rate contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	0.5
Total noncurrent derivative contracts, liabilities	0.2
Derivatives Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Total current derivative contracts, liabilities	0.7	0.8
Derivatives Not Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	5.1	4.3
Total noncurrent derivative contracts, assets		0.1
Total current derivative contracts, liabilities	8.7	8.1
Derivatives Not Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	1.3	1.7
Total current derivative contracts, liabilities	1.6	2.0
Derivatives Not Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	2.9	1.5
Total noncurrent derivative contracts, assets		0.1
Total current derivative contracts, liabilities	7.1	6.1
Derivatives Not Designated As Hedging Instruments | Other contracts
Fair Value Measurements
Total current derivative contracts, assets	$ 0.9	$ 1.1