Property, Plant and Equipment

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

Net property, plant and equipment is composed of the following:

	Depreciable Lives	As of December 31,
		2021		2020
		(Dollars in millions)
Property, plant and equipment:
Land	N/A	$	335	332
Fiber, conduit and other outside plant(1)	15-45 years	6,406		8,270
Central office and other network electronics(2)	7-10 years	5,106		4,964
Support assets(3)	3-30 years	2,721		2,679
Construction in progress(4)	N/A	491		411
Gross property, plant and equipment		15,059		16,656
Accumulated depreciation		(6,879)		(8,347)
Net property, plant and equipment		$	8,180	8,309

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(1)Fiber, conduit and other outside plant consists of fiber and metallic cable, conduit, poles and other supporting structures. Fiber, conduit and other outside plant decreased at December 31, 2021 compared to December 31, 2020 due to the retirement of a portion of our copper-based infrastructure being replaced with our Quantum Fiber infrastructure.

(2)Central office and other network electronics consists of circuit and packet switches, routers, transmission electronics and electronics providing service to customers.

(3)Support assets consist of buildings, computers and other administrative and support equipment.

(4)Construction in progress includes inventory held for construction and property of the aforementioned categories that has not been placed in service as it is still under construction.

We recorded depreciation expense of $833 million, $834 million and $831 million for the years ended December 31, 2021, 2020 and 2019, respectively.