Intangibles, net (Tables)

12 Months Ended

Dec. 31, 2018

Intangible Assets Net Excluding Goodwill [Abstract]

Identified Intangible Assets by Major Classification

Identified intangible assets by major classification, affected by the fluctuation of foreign currency rates, consist of the following (in millions):

			Accumulated			Net Book
	Gross		Amortization			Value
December 31, 2018:
Trademarks and patents	$	103	$	(31	)	$	72
Customer relationships		118		(46	)		72
Other		11		(11	)		—
Total identified intangibles	$	232	$	(88	)	$	144
December 31, 2017:
Trademarks and patents		104		(26	)		78
Customer relationships		122		(35	)		87
Other		11		(10	)		1
Total identified intangibles	$	237	$	(71	)	$	166

Schedule of Estimated Amortization of Intangible Assets

Amortization expense was $20 million, $22 million and $21 million for the years ended December 31, 2018, 2017, and 2016, respectively. The following table represents the total estimated amortization of intangible assets for the five succeeding years (in millions):

For the Year Ending December 31	Estimated Amortization Expense
2019	$	18
2020		18
2021		18
2022		17
2023		13