Fair Value Measurements and Disclosures (Details 3) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	[1]	$ 7,547	$ 7,626
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	[1]	$ 7,936	$ 7,105

[1] (1) Net of unamortized discount, premium and debt issuance costs and excludes capital lease and other obligations.