Derivatives And Hedging Activities Fair Value of Derivative Instruments in the Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net		$ 12	$ (37)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives		45	36
Gross amount of recognized liability derivatives		33	73
Designated as Hedging Instrument | Foreign Currency Derivative | Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives			6
Gross amount of recognized liability derivatives			3
Derivative, Fair Value, Net	[1]		3
Designated as Hedging Instrument | Foreign Currency Derivative | Other Long-Term Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives			8
Gross amount of recognized liability derivatives			4
Derivative, Fair Value, Net	[1]		4
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives			2
Gross amount of recognized liability derivatives			2
Not Designated as Hedging Instrument | Foreign Currency Derivative | Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives	[1]	0
Gross amount of recognized liability derivatives	[1]		1
Net amount of derivative liability presented in the Balance Sheet	[1]		(1)
Not Designated as Hedging Instrument | Foreign Currency Derivative | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives	[1]		2
Gross amount of recognized liability derivatives	[1]		1
Net amount of derivative liability presented in the Balance Sheet	[1]		1
Cash Flow Hedging | Designated as Hedging Instrument | Commodity Derivative | Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives		27	7
Cash Flow Hedging | Designated as Hedging Instrument | Commodity Derivative | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized liability derivatives		0	0
Cash Flow Hedging | Designated as Hedging Instrument | Commodity Derivative | Other Long-Term Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives		8	4
Cash Flow Hedging | Designated as Hedging Instrument | Commodity Derivative | Other Long-Term Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized liability derivatives		0	0
Cash Flow Hedging | Designated as Hedging Instrument | Foreign Currency Derivative | Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives	[1]	3
Gross amount of recognized liability derivatives	[1]	0
Net amount of derivative asset presented in the Balance Sheet	[1]	3
Cash Flow Hedging | Designated as Hedging Instrument | Foreign Currency Derivative | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives	[1]	7	9
Gross amount of recognized liability derivatives	[1]	17	55
Net amount of derivative liability presented in the Balance Sheet	[1]	(10)	(46)
Cash Flow Hedging | Designated as Hedging Instrument | Foreign Currency Derivative | Other Long-Term Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives	[1]	0	0
Gross amount of recognized liability derivatives	[1]	11	11
Net amount of derivative liability presented in the Balance Sheet	[1]	(11)	(11)
Net Investment Hedging | Designated as Hedging Instrument | Foreign Currency Derivative | Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of recognized asset derivatives		0	2
Net Investment Hedging | Designated as Hedging Instrument | Foreign Currency Derivative | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of recognized liability derivatives		$ 5	$ 0

[1] Derivative instruments within this category are subject to master netting arrangements and are presented on a net basis in the consolidated balance sheets in accordance with accounting guidance related to the offsetting of amounts related to certain contracts.