Financial Instruments (Notional Amounts of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	$ 282	$ 422
Not Designated as Hedging Instrument [Member] | Foreign Currency Contract [Member]
Derivative [Line Items]
Derivative notional amounts	7,342	9,896
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	$ 460	$ 7