Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Schedule of net property, plant and equipment

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

	Depreciable Lives	As of December 31,
		2020		2019
		(Dollars in millions)
Property, plant and equipment:
Land	N/A	$	332	332
Fiber, conduit and other outside plant(1)	15-45 years	8,270		7,735
Central office and other network electronics(2)	7-10 years	4,964		4,641
Support assets(3)	3-30 years	2,679		2,670
Construction in progress(4)	N/A	411		538
Gross property, plant and equipment		16,656		15,916
Accumulated depreciation		(8,347)		(7,746)
Net property, plant and equipment		$	8,309	8,170

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(1)Fiber, conduit and other outside plant consists of fiber and metallic cable, conduit, poles and other supporting structures.

(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.