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v3.20.4

Property, Plant and Equipment (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Property, Plant and Equipment [Line Items] |  |  |
Land | $ 34 | $ 35 |
Buildings | 295 | 295 |
Leasehold and land improvements | 1,369 | 1,280 |
Cell site equipment | 4,018 | 3,708 |
Switching equipment | 1,094 | 1,051 |
Office furniture and equipment | 282 | 280 |
Other operating assets and equipment | 49 | 48 |
System development | 1,327 | 1,238 |
Work in process | 317 | 358 |
Total property, plant and equipment, gross | 8,785 | 8,293 |
Accumulated depreciation and amortization | (6,319) | (6,086) |
Property, plant and equipment, net | 2,466 | 2,207 |
Depreciation and amortization expense | 669 | 689 | $ 627
Loss on asset disposals | $ 25 | $ 19 | $ 10
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 |  |

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