Commitments And Contingencies (Narrative) (Details) $ in Millions	1 Months Ended		3 Months Ended
	Sep. 30, 2018 property county item	Aug. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)
Regulatory Commitments [Abstract]
Number of States in our Territory			29
Number of auctions | item	2
FCC Inquiry [Member]
Regulatory Commitments [Abstract]
Award in funding | $		$ 200
CAF Phase II [ Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission | $			$ 332
Number of households to be serviced under regulatory funded programs			774,000
Auction 101 [Member]
Regulatory Commitments [Abstract]
Number of licenses | item	2
Number of counties | county	1,536
Auction 102 [Member]
Regulatory Commitments [Abstract]
Number of licenses | item	7
Number of economic areas | property	416
CTF Transaction [Member] | CAF Phase II [ Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission | $			$ 49