Intangible Assets, net

12 Months Ended

Dec. 31, 2019

Intangible Assets, net

Intangible Assets, net

Note 7. Intangible Assets, net

Intangible assets, net, consisted of the following:

		December 31, 2019				December 31, 2018
	Weighted Average	Gross				Gross
	Amortizable	Carrying		Accumulated		Carrying		Accumulated
	Life in Years	Amount		Amortization		Amount		Amortization
		(in millions)
Intangible assets subject to amortization:
Covenants not to compete	5.0	$	0.7	$	(0.4)	$	0.8	$	(0.4)
Customer lists/relationships	15.0		710.1		(438.1)		707.3		(393.4)
Software	10.0		8.1		(8.1)		8.1		(8.1)
Other	7.6		1.1		(0.9)		1.0		(0.9)
			720.0		(447.5)		717.2		(402.8)
Intangible assets not subject to amortization:
Trade names			758.6		—		757.6		—
		$	1,478.6	$	(447.5)	$	1,474.8	$	(402.8)

During 2018, we recognized impairment losses of $16.5 million and $16.7 million on our trade name and customer relationship intangible assets, respectively, related to one of our energy businesses. See Note 19 — “Impairment and Restructuring Charges” for further discussion of our impairment losses.

Amortization expense for intangible assets amounted to $43.1 million, $45.8 million and $50.6 million in 2019, 2018 and 2017, respectively. Foreign currency translation gains related to intangible assets, net in 2019 were $2.2 million.

The following is a summary of estimated aggregate amortization expense for each of the next five years:

	(in millions)
2020	$	43.2
2021		41.5
2022		36.7
2023		30.7
2024		27.2