Commitments And Contingencies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) state property	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Regulatory Commitments [Abstract]
Number of households to be serviced under regulatory funded programs | property	774,000
Number of states of operation | state	29
Operating Leases [Abstract]
Term Of Lease Arrangements Lower Range	1 year
Term Of Lease Arrangements Upper Range	99 years
Rental expense	$ 137,000,000	$ 119,000,000	$ 100,000,000
Loss Contingency, Estimate of Possible Loss	100,000
CAF Phase II [Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission	332,000,000
Verizon Transaction | CAF Phase II [Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission	$ 49,000,000