Debt and Other Obligations (Components of Interest Expense and Amortization of Deferred Financing Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt and Other Obligations [Abstract]
Interest Expense, Debt, Excluding Amortization	$ 169	$ 157	$ 336	$ 314
Amortization of deferred financing costs and adjustments on long-term debt	5	5	10	11
Other, net of capitalized interest	(5)	(4)	(9)	(7)
Interest expense and amortization of deferred financing costs	$ 169	$ 158	$ 337	$ 318