Summary Of Significant Accounting Policies (Schedule Of Revenues From External Customers) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 2,524	$ 1,424	$ 6,487	$ 4,163
Customer Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	2,319	1,223	5,889	3,692
Switched Access And Subsidy Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	205	201	598	471
Voice Services [Member]
Segment Reporting Information [Line Items]
Revenues	809	500	2,112	1,540
Data And Internet Services [Member]
Segment Reporting Information [Line Items]
Revenues	1,045	589	2,680	1,748
Video [Member]
Segment Reporting Information [Line Items]
Revenues	392	71	879	214
Other [Member]
Segment Reporting Information [Line Items]
Revenues	$ 73	$ 63	$ 218	$ 190