The changes in the carrying amounts of goodwill during the years ended December 31, 2022, 2021 and 2020 were as follows:


(millions)	Commercial			Aviation			Total
Net book values as of January 1, 2021 and December 31, 2021
Goodwill	$	377.1		$	209.0		$	586.1
Accumulated impairment losses		—			(59.5	)		(59.5	)
Total	$	377.1		$	149.5		$	526.6
Acquisitions		10.1			6.2			16.3
Foreign currency translation		(0.2	)		0.5			0.3
Net book value as of December 31, 2022
Goodwill	$	387.0		$	215.7		$	602.7
Accumulated impairment losses		—			(59.5	)		(59.5	)
Total	$	387.0		$	156.2		$	543.2

As discussed in Note 1. Significant Accounting Policies and Practices, due to the impacts of COVID-19, revenues for certain markets in which the Company operates dropped significantly during 2020 as compared to the expectations as of the October 1, 2019 annual impairment test. As a result, the Company recorded a $59.5 million impairment charge during the year ended December 31, 2020, which was recognized in Impairment of goodwill and intangible assets within the Consolidated Statements of Income (Loss). The fair value of goodwill was classified as Level 3 in the fair value hierarchy. See Note 11. Fair Value Measurement for further discussion.