Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Outstanding commodity derivatives contracts not designated as hedging instruments
Net losses from derivatives not designated as hedging instruments recognized in net sales (in dollars)	$ 26	$ 12
CO2 (in cubic feet)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	616,000,000,000	621,000,000,000
Oil (in barrels)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	(14,000,000)	(9,000,000)
Natural Gas (in cubic feet)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	(25,000,000,000)	(32,000,000,000)