Goodwill - Schedule of Changes in Carrying Amounts of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2021
Goodwill [Line Items]
Goodwill	$ 586.1	$ 586.2
Accumulated impairment losses	(59.5)	(59.5)
Total	526.6	526.7
Foreign currency translation	0.1
Commercial
Goodwill [Line Items]
Goodwill	377.1	377.2
Accumulated impairment losses	0.0	0.0
Total	377.1	377.2
Foreign currency translation	0.1
Aviation
Goodwill [Line Items]
Goodwill	209.0	209.0
Accumulated impairment losses	(59.5)	(59.5)
Total	149.5	$ 149.5
Foreign currency translation	$ 0.0