Fair Value Measurements. Other Financial Instruments (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Estimated Fair Value Of Debt, Including Current Portion
Carrying amount (excluding capital leases)	$ 7,595	$ 8,300
Fair value	$ 9,169	$ 9,492

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant