Accounting Principles and Practices (Narrative) (Details) $ in Millions	Dec. 31, 2015 USD ($)
Accounting Standard Update 2015-03 [Member] | Other Current Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred financing costs	$ 4
Accounting Standard Update 2015-03 [Member] | Other Noncurrent Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred financing costs	33
Accounting Standard Update 2015-03 [Member] | Long-term Debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred financing costs	(37)
New Accounting Pronouncement, Early Adoption, Effect [Member] | Non-current Deferred Tax Asset [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax asset, net	92
New Accounting Pronouncement, Early Adoption, Effect [Member] | Non-current Deferred Tax Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax asset, net	$ (139)