Derivatives (Details 1) item in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) item	Mar. 31, 2015 USD ($)	Dec. 31, 2015 item
Net sales
Outstanding commodity derivatives contracts not designated as hedging instruments
Net losses from derivatives not designated as hedging instruments recognized in net sales (in dollars) | $	$ 13	$ 26
CO2 (in cubic feet) | Long position
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position	587,000		603,000
Oil (in barrels) | Long position
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position	152		83
Natural Gas (in cubic feet) | Short position
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position	84,000		58,000