Financial Instruments and Risk Management - Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Measurements
Total current derivative contracts, assets	$ 40.0	$ 21.0
Total noncurrent derivative contracts, assets	46.0	3.0
Total current derivative contracts, liabilities	$ 25.0	50.0
Total noncurrent derivative contracts, liabilities		$ 31.0
Discount factor	12 month LIBOR	12-month LIBOR
Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	$ 18.0	$ 10.0
Total noncurrent derivative contracts, assets	7.0	1.0
Total current derivative contracts, liabilities	3.0	17.0
Total noncurrent derivative contracts, liabilities		8.0
Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	1.0	8.0
Total current derivative contracts, liabilities	22.0	33.0
Other contracts
Fair Value Measurements
Total current derivative contracts, assets	21.0	3.0
Total noncurrent derivative contracts, liabilities		23.0
Interest rate and other contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	39.0	2.0
Derivatives Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	18.0	8.0
Total noncurrent derivative contracts, assets	46.0	1.0
Total current derivative contracts, liabilities	3.0	12.0
Total noncurrent derivative contracts, liabilities		8.0
Derivatives Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	17.0	6.0
Total noncurrent derivative contracts, assets	7.0	1.0
Total current derivative contracts, liabilities	3.0	12.0
Total noncurrent derivative contracts, liabilities		8.0
Derivatives Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets	1.0	2.0
Derivatives Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets	39.0
Derivatives Not Designated As Hedging Instruments
Fair Value Measurements
Total current derivative contracts, assets	22.0	13.0
Total noncurrent derivative contracts, assets		2.0
Total current derivative contracts, liabilities	22.0	38.0
Total noncurrent derivative contracts, liabilities		23.0
Derivatives Not Designated As Hedging Instruments | Commodity contracts
Fair Value Measurements
Total current derivative contracts, assets	1.0	4.0
Total current derivative contracts, liabilities		5.0
Derivatives Not Designated As Hedging Instruments | Foreign currency contracts
Fair Value Measurements
Total current derivative contracts, assets		6.0
Total current derivative contracts, liabilities	22.0	33.0
Derivatives Not Designated As Hedging Instruments | Other contracts
Fair Value Measurements
Total current derivative contracts, assets	$ 21.0	3.0
Total noncurrent derivative contracts, liabilities		23.0
Derivatives Not Designated As Hedging Instruments | Interest rate and other contracts
Fair Value Measurements
Total noncurrent derivative contracts, assets		$ 2.0