Reportable Business Segments (Assets by Segment) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Total assets	$ 3,455.4	$ 3,471.8
Residential Heating and Cooling [Member]
Segment Reporting Information [Line Items]
Total assets	1,761.6	1,626.0
Commercial Heating and Cooling
Segment Reporting Information [Line Items]
Total assets	1,108.0	1,052.6
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 585.8	$ 793.2