Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		$ 0
Defined Benefit Plan, Transfers Between Measurement Levels	0	0
Long-term Debt, Fair Value		1,921,000,000	1,949,000,000
Long-term Debt		1,736,000,000	1,636,000,000
Cash Surrender Value, Fair Value Disclosure		$ 24,000,000	$ 23,000,000

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This element represents the portion of a balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount that could be realized under a life insurance contract or contracts owned by the Company as of the date of the statement of financial position. Such Company-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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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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