Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Finite-Lived Intangible Assets

The components of intangible assets were as follows:

	December 31, 2017							December 31, 2016
	Gross					Net		Gross					Net
	Carrying		Accumulated			Intangible		Carrying		Accumulated			Intangible
(Dollars in millions)	Amount		Amortization			Assets		Amount		Amortization			Assets
Acquired technology	$	390	$	(334	)	$	56	$	373	$	(300	)	$	73
Licenses	175		(168		)	7		177		(166		)	11
Patents	223		(144		)	79		215		(134		)	81
Customer Relationships and Contracts	197		(160		)	37		193		(144		)	49
Other	98		(64		)	34		91		(57		)	34
	$	1,083	$	(870	)	$	213	$	1,049	$	(801	)	$	248

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense

Future estimated amortization expense for the carrying amount of intangible assets as of December 31, 2017 is expected to be as follows (dollars in millions): 

Period	Amount
2018	$	48
2019	42
2020	32
2021	20
2022	13