Goodwill (Tables)

9 Months Ended

Sep. 30, 2021

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amounts of Goodwill

There were no changes to the carrying amount of goodwill for the nine months ended September 30, 2021 (unaudited). The balances for each segment were as follows:

(millions)	Commercial		Aviation			Total
Net book value as of September 30, 2021 and  December 31, 2020
Goodwill	$	377.1	$	209.0		$	586.1
Accumulated impairment losses		—		(59.5	)		(59.5	)
Total	$	377.1	$	149.5		$	526.6