Property, Plant And Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant And Equipment [Abstract]

Property, Plant And Equipment

(5)  Property, Plant and Equipment:

Property, plant and equipment, net at December 31, 2017 and 2016 are as follows:

($ in millions)	Estimated Useful Lives	2017		2016
Land	N/A	$	231	$	235
Buildings and leasehold improvements	41 years		2,282		2,320
General support	5 to 17 years		1,570		1,502
Central office/electronic circuit equipment	5 to 18 years		8,137		7,683
Poles	30 years		1,095		995
Cable, fiber and wire	15 to 25 years		10,997		10,292
Conduit	55 years		1,646		1,611
Construction work in progress			538		903
Property, plant and equipment			26,496		25,541
Less: Accumulated depreciation			(12,119)		(10,639)
Property, plant and equipment, net		$	14,377	$	14,902

Property, plant, and equipment includes approximately $171 million and $154 million of fixed assets recognized under capital leases as of December 31, 2017 and 2016, respectively.

In 2017, we sold certain properties, generating $102 million in net proceeds, of which $97 million relates to property subject to leasebacks. For these properties, we have deferred $66 million in related gains that will be amortized over the related lease terms of two years. For year ended December 31, 2017, amortization of these deferred gains totaled $23 million, which are included in “Selling, general and administrative expenses” on our consolidated income statement. We have remaining deferred gain balances of $43 million, which are included in “Other liabilities.”

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

	For the Year Ended
($ in millions)	2017		2016		2015
Depreciation expense	$	1,485	$	1,388	$	983

We adopted new estimated remaining useful lives for certain plant assets as of October 1, 2017, 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.