Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income	$ 8.5	$ (8.2)	$ 22.5	$ (2.8)
Derivative activity:
Change in derivative fair value, net of income tax	0.0	0.1	0.0	0.0
Reclassification of earnings, net of income tax	(0.2)	(0.3)	(0.6)	(0.8)
Total change in fair value of derivatives	(0.2)	(0.2)	(0.6)	(0.8)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	0.1	0.0	0.4	(0.1)
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.5	0.3	1.5	0.8
Total change in unfunded pension obligation	0.5	0.3	1.5	0.8
Other comprehensive income	0.3	0.1	0.9	0.0
Net comprehensive income / (loss)	8.8	(8.1)	23.4	(2.8)
Subsidiaries [Member]
Net income	13.4	17.8	40.3	47.3
Derivative activity:
Change in derivative fair value, net of income tax	0.0	0.2	0.0	0.1
Reclassification of earnings, net of income tax	0.0	(0.1)	0.0	(0.3)
Total change in fair value of derivatives	0.0	0.1	0.0	(0.2)
Pension and postretirement activity:
Reclassification to earnings, net of income tax	1.0	0.8	2.9	2.4
Total change in unfunded pension obligation	1.0	0.8	2.9	2.4
Other comprehensive income	1.0	0.9	2.9	2.2
Net comprehensive income / (loss)	$ 14.4	$ 18.7	$ 43.2	$ 49.5