Fair Value Disclosures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Dec. 31, 2011
Fair Value Additional Information [Abstract]
Carrying value of long term debt	$ 6,600	$ 6,225
Asset Impairment Charges	21
Assets and Liabilities Measure on a Recurring Basis [Abstract]
Derivative Assets	32	37
Level 2
Assets and Liabilities Measure on a Recurring Basis [Abstract]
Derivative Assets	32	37
Derivative Liability	1	4
Fair value of long term debt	$ 7,025	$ 6,692

The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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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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- Definition

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

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- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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