Supplemental Consolidated Cash and Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Supplemental Cash Flow Elements [Abstract]
Cash	$ 38.9		$ 21.8
Restricted cash	1.3		0.5
Total cash and restricted cash reported in the Consolidated Balance Sheets	40.2	$ 65.5	$ 22.3	$ 25.5
Cash paid (recovered) during the nine months for interest	7.3	9.3
Cash paid (recovered) during the nine months for income taxes	$ 20.2	$ 18.5