Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Land	$ 37	$ 37
Buildings	281	293
Leasehold and land improvements	1,504	1,442
Cell site equipment	4,247	4,150
Switching equipment	1,115	1,095
Office furniture and equipment	209	252
Other operating assets and equipment	47	47
System development	1,676	1,479
Work in process	218	261
Total property, plant and equipment, gross	9,334	9,056
Accumulated depreciation and amortization	(6,710)	(6,450)
Property, plant and equipment, net	2,624	2,606
Depreciation and amortization expense	682	662	$ 669
(Gain) loss on asset disposals, net	$ 19	$ 23	$ 25
Buildings
Property, Plant and Equipment [Line Items]
Useful life	20 years
Leasehold and land improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
Leasehold and land improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	30 years
Cell site equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	7 years
Cell site equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Switching equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Switching equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	8 years
Office furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Office furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Other operating assets and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Other operating assets and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
System development | Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
System development | Maximum
Property, Plant and Equipment [Line Items]
Useful life	7 years