Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Long-term debt and short-term borrowings
Long-term Debt, Total	$ 2,200	$ 2,197
Less current maturities	(552)	(3)
Long-term debt	1,648	2,194
Revolving Credit Facility, maturing 2013 [Member]
Long-term debt and short-term borrowings
Credit Agreement
Senior Notes, interest at 6.25%, maturing 2013 [Member]
Long-term debt and short-term borrowings
Senior Notes	500	500
Senior Notes, interest at 7.875%, maturing 2014 [Member]
Long-term debt and short-term borrowings
Senior Notes	498	497
Senior Notes interest at 7.375%, maturing 2015 [Member]
Long-term debt and short-term borrowings
Senior Notes	450	450
Senior Notes, interest at 6.75%, maturing 2018 [Member]
Long-term debt and short-term borrowings
Senior Notes	400	400
Senior Notes, interest at 7.15%, maturing 2019 [Member]
Long-term debt and short-term borrowings
Senior Notes	245	245
Mortgages and other, interest rates ranging from 1.00% to 9.00%, various maturities [Member]
Long-term debt and short-term borrowings
Long-term debt	$ 107	$ 105

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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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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