Acquisitions (Details) $ in Thousands, customer in Millions				3 Months Ended
	Mar. 08, 2021 item	Jul. 01, 2020 USD ($) customer	Jul. 26, 2019 USD ($)	Mar. 31, 2021 USD ($) item store	Sep. 11, 2020 USD ($)
Business Acquisition [Line Items]
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 | store				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 Purchase Application Deadline				3 years
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
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
Intangibles		591,000
Goodwill		$ 91,220
Boost Mobile Aquisition [Member] | Minimum
Business Acquisition [Line Items]
Number Of Retail Wireless Subscribers Acquired | customer		9
Useful life		1 year
Boost Mobile Aquisition [Member] | Maximum
Business Acquisition [Line Items]
Useful life		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
Republic Wireless Inc
Business Acquisition [Line Items]
Number Of Retail Wireless Subscribers Acquired | item	200,000