Credit Facilities and Long-Term Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Sep. 20, 2011
Debt Instrument
Short-term borrowings and current maturities of long-term debt	$ 6	$ 6
Credit Facilities and Long-Term Debt :
Unamortized discount	(1)	(1)
Long-term debt	1,199	1,199
Total debt	1,205	1,205
Senior Notes Due 2016, 3.550%
Credit Facilities and Long-Term Debt :
Senior Notes Due	600	600	600
Senior Notes Due 2021, 4.875%
Credit Facilities and Long-Term Debt :
Senior Notes Due	$ 600	$ 600	$ 600

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). 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.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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