Derivatives - Balance Sheet Location (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	$ 522.9	$ 695.3
Derivative liability	468.7	649.6
Derivatives designated as hedging instruments
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	127.7	23.5
Derivative liability	98.2	1.7
Derivatives designated as hedging instruments | Commodity contracts | Short-term derivative assets, net
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	114.0	18.8
Derivative liability	95.3	1.0
Derivatives designated as hedging instruments | Commodity contracts | Long-term derivative assets, net
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	7.4
Derivatives designated as hedging instruments | Commodity contracts | Accrued expenses and other current liabilities
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	6.3	4.7
Derivative liability	2.9	0.7
Derivatives not designated as hedging instruments
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	395.2	671.8
Derivative liability	370.5	647.9
Derivatives not designated as hedging instruments | Commodity contracts | Short-term derivative assets, net
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	241.4	399.0
Derivative liability	26.6	76.0
Derivatives not designated as hedging instruments | Commodity contracts | Identifiable intangible and other non-current assets
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	17.0	12.1
Derivative liability	4.8	0.6
Derivatives not designated as hedging instruments | Commodity contracts | Accrued expenses and other current liabilities
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	120.4	234.1
Derivative liability	319.9	530.0
Derivatives not designated as hedging instruments | Commodity contracts | Other long-term liabilities
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	4.0	4.8
Derivative liability	14.2	29.3
Derivatives not designated as hedging instruments | Foreign currency contracts | Short-term derivative assets, net
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	10.9	21.3
Derivative liability	3.3	12.0
Derivatives not designated as hedging instruments | Foreign currency contracts | Identifiable intangible and other non-current assets
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	0.7	$ 0.5
Derivatives not designated as hedging instruments | Foreign currency contracts | Accrued expenses and other current liabilities
Information about derivative instruments measured at fair value and their locations on the consolidated balance sheet
Derivative asset	0.8
Derivative liability	$ 1.7