Derivatives (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Outstanding commodity derivatives contracts not designated as hedging instruments
Net gains from derivatives not designated as hedging instruments recognized in net sales (in dollars)	$ (71)	$ 11
CO2 (in cubic feet)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	621,000,000
Oil (in barrels)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	(9,000,000)	(22,000,000)
Natural Gas (in cubic feet)
Outstanding commodity derivatives contracts not designated as hedging instruments
Net Outstanding Position Long/(Short)	(32,000,000,000)	(10,000,000,000)