Financial Instruments (Notional Amounts of Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Designated as Hedging Instrument [Member] | Foreign Currency Contract [Member]
Derivative [Line Items]
Derivative notional amounts	$ 1	$ 10
Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	265	356
Not Designated as Hedging Instrument [Member] | Foreign Currency Contract [Member]
Derivative [Line Items]
Derivative notional amounts	9,320	8,065
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	$ 16	$ 70