Goodwill

6 Months Ended

Jun. 30, 2021

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill

7. Goodwill

The changes to the carrying amount of goodwill for the six months ended June 30, 2021 (unaudited) were as follows:

(millions)	Commercial		Aviation			Total
Net book value as of December 31, 2020
Goodwill	$	377.1	$	209.0		$	586.1
Accumulated impairment losses		—		(59.5	)		(59.5	)
Total	$	377.1	$	149.5		$	526.6
Foreign currency translation		0.1		—			0.1
Net book value as of June 30, 2021
Goodwill	$	377.2	$	209.0		$	586.2
Accumulated impairment losses		—		(59.5	)		(59.5	)
Total	$	377.2	$	149.5		$	526.7