Fair Value Measurements (Carrying Amount And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, net	$ (131)	$ (2)
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	998	15
Credit facility		116
Senior notes	3,844	3,842
Derivative instruments, net	(131)	(2)
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	998	15
Credit facility		116
Senior notes	3,580	2,651
Derivative instruments, net	(131)	(2)
Long-term Debt [Member] | Carrying Amount [Member] | Term Loan due November 2018 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	744	747
Long-term Debt [Member] | Carrying Amount [Member] | Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	1,180
Long-term Debt [Member] | Fair Value [Member] | Term Loan due November 2018 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	744	$ 747
Long-term Debt [Member] | Fair Value [Member] | Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 1,180