Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of finite-lived intangible assets

	December 31, 2017							December 31, 2016
	Weighted Average Useful Life (Years)	Gross Value		Accumulated Amortization		Net Value		Gross Value		Accumulated Amortization		Net Value
		(In millions)
Customer relationships	9.2	$	83.4	$	29.3	$	54.1	$	75.5	$	23.7	$	51.8
Indefinite-lived tradenames	*	23.7		*		23.7		22.4		*		22.4
Technology	17.5	23.6		3.0		20.6		23.0		1.8		21.2
Other	7.2	4.1		3.0		1.1		4.0		2.8		1.2
Total		$	134.8	$	35.3	$	99.5	$	124.9	$	28.3	$	96.6
* Not applicable, as these tradenames have an indefinite life.

Schedule of indefinite-lived intangible assets

	December 31, 2017							December 31, 2016
	Weighted Average Useful Life (Years)	Gross Value		Accumulated Amortization		Net Value		Gross Value		Accumulated Amortization		Net Value
		(In millions)
Customer relationships	9.2	$	83.4	$	29.3	$	54.1	$	75.5	$	23.7	$	51.8
Indefinite-lived tradenames	*	23.7		*		23.7		22.4		*		22.4
Technology	17.5	23.6		3.0		20.6		23.0		1.8		21.2
Other	7.2	4.1		3.0		1.1		4.0		2.8		1.2
Total		$	134.8	$	35.3	$	99.5	$	124.9	$	28.3	$	96.6
* Not applicable, as these tradenames have an indefinite life.

Schedule of amortization of intangible assets

Amortization expense of other intangible assets follows:

	Year Ended December 31,
	2017		2016		2015
	(In millions)
Amortization expense	$	6.6	$	6.1	$	6.4

Amortization for the next five years

We estimate amortization expense for the five years subsequent to December 31, 2017 as follows:

	(In millions)
2018	$	6.8
2019	$	6.4
2020	$	6.2
2021	$	6.2
2022	$	6.2