Debt and Other Obligations (Components of Interest Expense and Amortization of Deferred Financing Costs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Debt and Other Obligations [Abstract]
Interest expense on debt obligations	$ 158	$ 132
Amortization of deferred financing costs and adjustments on long-term debt	5	4
Other	(3)	(2)
Total	$ 160	$ 134