Summary Of Significant Accounting Policies (Schedule Of Revenues From External Customers) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 2,608	$ 1,368	$ 3,963	$ 2,739
Customer Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	2,381	1,236	3,570	2,469
Switched Access And Subsidy Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	227	132	393	270
Voice Services [Member]
Segment Reporting Information [Line Items]
Revenues	836	515	1,303	1,040
Data And Internet Services [Member]
Segment Reporting Information [Line Items]
Revenues	1,048	584	1,635	1,159
Video [Member]
Segment Reporting Information [Line Items]
Revenues	419	72	487	143
Other Customer Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	$ 78	$ 65	$ 145	$ 127