Property, Plant And Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant And Equipment [Abstract]

Property, Plant And Equipment

(5)   Property, Plant and Equipment:

Property, plant and equipment, net at December 31, 2016 and 2015 are as follows:

($ in millions)	Estimated Useful Lives	2016		2015
Land	N/A	$	235	$	151
Buildings and leasehold improvements	41 years		2,300		1,327
General support	5 to 17 years		1,495		1,146
Central office/electronic circuit equipment	5 to 18 years		7,683		6,244
Poles	30 years		995		712
Cable, fiber and wire	15 to 25 years		10,267		7,280
Conduit	55 years		1,611		515
Other	12 to 25 years		52		47
Construction work in progress			903		379
Property, plant and equipment			25,541		17,801
Less: Accumulated depreciation			(10,639)		(9,308)
Property, plant and equipment, net		$	14,902	$	8,493

Property, plant, and equipment includes approximately $154 million and $43 million of fixed assets recognized under capital leases as of December 31, 2016 and 2015, respectively.

Depreciation expense is principally based on the composite group method. Depreciation expense was as follows:

	For the Year Ended
($ in millions)	2016		2015		2014
Depreciation expense	$	1,388	$	983	$	835

We adopted new estimated remaining useful lives for certain plant assets as of October 1, 2016, as a result of an annual independent study of the estimated remaining useful lives of our plant assets, with an insignificant impact to depreciation expense. In addition, the estimated useful lives for assets acquired in the CTF Acquisition were adopted for such assets based on a similar study performed as of October 1, 2015 and were effective April 1, 2016.