Commitments And Contingencies (Narrative) (Details) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 30, 2020 USD ($) state item	Mar. 31, 2023	Dec. 31, 2015 USD ($) state
Commitments And Contingencies [Line Items]
Short-term purchase commitment, period		2 years
Short-term purchase commitment, extension period		2 years
RDOF Program, Phase I [Member]
Commitments And Contingencies [Line Items]
Awarded amount | $	$ 371
Period to build gigabit capable broadband	10 years
Number of location to build gigabit capable broadband | item	127,000
Number of states to build gigabit capable broadband | state	8
RDOF Program, Phase II [Member]
Commitments And Contingencies [Line Items]
Annual support offered by the Federal Communications Commission | $			$ 313
Number of states in offer | state			25
Minimum [Member]
Commitments And Contingencies [Line Items]
Terms of lease arrangements		1 year
Maximum [Member]
Commitments And Contingencies [Line Items]
Terms of lease arrangements		99 years