Derivative Financial Instruments (Fair Values Of Outstanding Derivative Instruments In The Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	$ 30	$ 19
Derivative liabilities, fair value	38	82
Fair Value, Inputs, Level 1 [Member] | Other current assets [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, commodity contracts	9	4
Fair Value, Inputs, Level 1 [Member] | Other non-current assets [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, commodity contracts	3	0
Fair Value, Inputs, Level 1 [Member] | Accounts payable and accrued liabilities [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities, commodity contracts	19	56
Fair Value, Inputs, Level 1 [Member] | Other non-current liabilities [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities, commodity contracts	3	6
Fair Value, Inputs, Level 2 [Member] | Other current assets [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, Foreign exchange contracts	12	9
Fair Value, Inputs, Level 2 [Member] | Other current assets [Member] | Not Designated As Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative assets, Foreign exchange contracts	6	6
Fair Value, Inputs, Level 2 [Member] | Accounts payable and accrued liabilities [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilites, Foreign exchange contracts	11	10
Fair Value, Inputs, Level 2 [Member] | Accounts payable and accrued liabilities [Member] | Not Designated As Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilites, Foreign exchange contracts	$ 5	$ 10