Financial Instruments (Notional Amounts of Derivatives) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative notional amounts	$ 0	$ 1,000
Designated as Hedging Instrument [Member] | Foreign Currency Contract [Member]
Derivative [Line Items]
Derivative notional amounts	71	434
Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	265	388
Not Designated as Hedging Instrument [Member] | Foreign Currency Contract [Member]
Derivative [Line Items]
Derivative notional amounts	8,959	10,586
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Derivative notional amounts	$ 86	$ 166