Derivative Financial Instruments (Fair Values Of Outstanding Derivative Instruments In The Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	$ 17	$ 22
Derivative liabilities, fair value	70	30
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Asset, Fair Value, Net	17	22
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	2	7
Derivative Assets	15	15
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Net	70	30
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	2	7
Derivative Liabilities	68	23
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	0	5
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	0	1
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	34	17
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	4	3
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	15	5
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	2	11
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	20	6
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	$ 12	$ 4

Fair value of the gross assets less the gross liabilities of a derivative asset or group of derivative assets.

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The amount as of the balance sheet date of the fair value of derivative assets that in accordance with the entity's accounting policy was not offset against an obligation to return cash collateral under a master netting arrangement.

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The amount as of the balance sheet date of the fair value of derivative assets that in accordance with the entity's accounting policy was offset against an obligation to return cash collateral under a master netting arrangement.

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Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy was not offset against the right to reclaim cash collateral under a master netting arrangement.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy were offset against the right to reclaim cash collateral under a master netting arrangement.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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Fair value of the gross liabilities less the gross assets of a derivative liability or group of derivative liabilities.

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Fair value as of the balance sheet date of foreign currency derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets on the balance sheet.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities on the balance sheet.

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Fair value as of the balance sheet date of price risk derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets on the balance sheet.

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Fair value as of the balance sheet date of price risk derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities on the balance sheet.

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