Acquisitions (Details) $ in Thousands, customer in Millions			12 Months Ended
	Jul. 01, 2020 USD ($) customer	Jul. 26, 2019 USD ($)	Dec. 31, 2020 USD ($) item	Sep. 11, 2020 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Goodwill					$ 126,000
Annual Lease payment				$ 56,000
Master Network Service Agreement
Business Acquisition [Line Items]
Maximum permitted ownership percent			50.00%
Master Network Service Agreement Period			7 years
Service Receipt Period			2 years
Service receipt period			2 years
Provision For New User After Change Of Control			6 months
Threshold Ownership Percentage Of Not Permitted Owners			50.00%
service pass through costs and out of pocket expenses charging period			36 months
Percentage Of Wireless Communication Business Assets Are Sold			50.00%
Percentage Of Voting Power Or Economic Value Held By Restricted Persons			50.00%
Option Agreement
Business Acquisition [Line Items]
Spectrum Lease Period		6 years
Number of cell sites | item			20,000
Number of retail stores | item			400
Period in which cell sites are scheduled to be decommissioned			5 years
Option agreement term			5 years
Period after closing of prepaid business sale, transfer asset request is admissible		1 year
Period within closing of prepaid business sale, required to offer nationwide postpaid retail mobile wireless service		1 year
Percentage of purchase price		10.00%
Percentage of population served		20.00%
Period in which at least 20% of population served to avoid payment of damages		3 years
Period obliged to provide DOJ with description of deployment efforts		180 days
Damages To Be Paid In Case Of Breach Of Agreement		$ 360,000
Transition Services Agreement
Business Acquisition [Line Items]
Transaction Agreements Period After Provision New Or Existing Customers Of Prepaid Business	2 years
Transition Services Agreement Provided At Cost Period	2 years
Spectrum Purchase Agreement.
Business Acquisition [Line Items]
Period of spectrum divestiture extend			60 days
Period within which divesture to be completed after receipt of FCC approval			3 years
Threshold divesture deadline extension period			5 days
Spectrum lease back period			2 years
per-Pop rate			$ 68,000
Decrease in purchase price due to failure to complete rebanding activities			72,000
Damages sought value in case of breach of agreement			$ 72,000
Minimum
Business Acquisition [Line Items]
Useful life			5 years
Maximum
Business Acquisition [Line Items]
Useful life			20 years
600 MHz Licenses | Minimum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		70.00%
600 MHz Licenses | Maximum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		75.00%
AWS-4 Satellites | Option Agreement
Business Acquisition [Line Items]
Damages To Be Paid In Case Of Breach Of Agreement		$ 2,200,000
AWS-4 Satellites | Minimum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		20.00%
AWS-4 Satellites | Maximum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		70.00%
700 MHz Licenses | Minimum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		20.00%
700 MHz Licenses | Maximum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		70.00%
AWS H Block licenses | Minimum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		20.00%
AWS H Block licenses | Maximum
Business Acquisition [Line Items]
Percent Of Coverage On Available Licensed Geographic Areas		70.00%
Aws4 And 600 Mhz
Business Acquisition [Line Items]
No sale agreement period			6 years
Boost Mobile Aquisition [Member]
Business Acquisition [Line Items]
Total consideration	$ 1,346,024
Trade accounts receivable and allowance for credit losses	539,000
Allowance for credit losses	24,000
Inventory	141,718
Amount of below market contracts acquired as intangible assets	37,000
Spectrum purchase option fair value	713,000		$ 713,000
Intangibles	591,000
Goodwill	$ 91,220
Boost Mobile Aquisition [Member] | Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition related transaction costs			$ 13,000
Boost Mobile Aquisition [Member] | Minimum
Business Acquisition [Line Items]
Number Of Retail Wireless Subscribers Acquired | customer	9
Useful life	1 year		1 year
Boost Mobile Aquisition [Member] | Maximum
Business Acquisition [Line Items]
Useful life	10 years		10 years
Boost Mobile Aquisition [Member] | Customer relationships
Business Acquisition [Line Items]
Intangibles	$ 458,000
Boost Mobile Aquisition [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Intangibles	$ 96,000
2020 Acquisition | Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Acquisition related transaction costs			$ 13,000