Other Intangible Assets

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Other Intangible Assets

Other Intangible Assets

	December 31, 2019							December 31, 2018
	Weighted Average Remaining Useful Life (Years)	Gross Value		Accumulated Amortization		Net Value		Gross Value		Accumulated Amortization		Net Value
Customer relationships	10.0	$	86.6	$	39.6	$	47.0	$	86.0	$	34.5	$	51.5
Indefinite-lived tradenames	*	24.6		*		24.6		24.1		*		24.1
Technology	15.5	22.9		5.3		17.6		22.9		4.1		18.8
Other	7.5	4.8		3.4		1.4		4.1		3.2		0.9
Total		$	138.9	$	48.3	$	90.6	$	137.1	$	41.8	$	95.3
* Not applicable, as these tradenames have an indefinite life.

Amortization expense of other intangible assets as follows:

	Year Ended December 31,
	2019		2018		2017
Amortization expense	$	6.5	$	6.9	$	6.6

We estimate amortization expense for the five years subsequent to December 31, 2019 as follows:

2020	$	6.5
2021	$	6.5
2022	$	6.4
2023	$	6.3
2024	$	6.1