Financial Instruments Notional Amounts (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 351	$ 525
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	125	9
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 1,442	$ 2,057