Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

Property, plant and equipment are recorded at cost. Depreciation and amortization for our property, plant and equipment are computed using the straight-line method based on the following estimated useful lives:

Facility and Leasehold Improvements	15	-	40	years
Network Infrastructure (including fiber and conduit)	25	-	50	years
Operating Equipment	5	-	15	years
Furniture, Fixtures, Office Equipment and Other	3	-	7	years

We perform internal reviews to evaluate the depreciable lives of our property, plant and equipment annually, or more frequently if new facts and circumstances arise, that may affect management's original estimates. Due to the rapid changes in technology and the competitive environment, selecting the estimated economic life of telecommunications property, plant, and equipment requires a significant amount of judgment. Our internal reviews take into account input from our global engineering and network services personnel, actual usage, the physical condition of our property, plant, and equipment, industry data, and other relevant factors. In connection with our periodic review of the estimated useful lives of property, plant and equipment, we may determine that the period we expect to use certain assets is different than the remaining previously estimated useful lives.

The components of our property, plant and equipment as of December 31, 2016 and 2015 are as follows (dollars in millions):

	Cost		Accumulated Depreciation			Net
December 31, 2016
Land	$	179	$	—		$	179
Land Improvements	77		(58		)	19
Facility and Leasehold Improvements	2,679		(1,447		)	1,232
Network Infrastructure	9,110		(3,899		)	5,211
Operating Equipment	8,846		(5,626		)	3,220
Furniture, Fixtures and Office Equipment	241		(196		)	45
Other	26		(23		)	3
Construction-in-Progress	230		—			230
	$	21,388	$	(11,249	)	$	10,139
December 31, 2015
Land	$	180	$	—		$	180
Land Improvements	76		(53		)	23
Facility and Leasehold Improvements	2,582		(1,352		)	1,230
Network Infrastructure	8,979		(3,669		)	5,310
Operating Equipment	7,988		(5,079		)	2,909
Furniture, Fixtures and Office Equipment	242		(189		)	53
Other	28		(23		)	5
Construction-in-Progress	168		—			168
	$	20,243	$	(10,365	)	$	9,878