Other Intangible Assets

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Other intangible assets, net consists of the following (in millions):



	December 31, 2018							December 31, 2017
	Gross carrying amount		Accumulated amortization			Net carrying amount		Gross carrying amount		Accumulated amortization			Net carrying amount
Customer relationships	$	568.0	$	(382.8	)	$	185.2	$	555.9	$	(326.0	)	$	229.9
Other	6.9		(4.1		)	2.8		5.3		(3.6		)	1.7
Total intangible assets	$	574.9	$	(386.9	)	$	188.0	$	561.2	$	(329.6	)	$	231.6

Intangible assets, other than those with indefinite lives, are amortized over their estimated useful lives ranging from 3 to 10 years from the acquisition date using either a straight-line or accelerated method.

Estimated amortization expense on other intangible assets for the next five fiscal years is as follows (in millions):



2019	$	58.2
2020	47.2
2021	36.3
2022	25.2
2023	14.2