Reportable Business Segments (Key Financial Information by Segment) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting Information [Line Items]
Net sales	$ 1,572.5	$ 1,426.8	$ 4,252.9	$ 4,000.3
Cost of goods sold			2,863.1	2,652.8
Selling, general and administrative			496.5	450.4
Other (income) expense			(8.1)	(13.8)
Segment Profit And Loss	323.3	328.8	841.8	845.8
Operating Segments
Segment Reporting Information [Line Items]
Net sales	1,572.5	1,426.8
Cost of goods sold	1,074.4	938.6
Selling, general and administrative	161.7	139.1
Other (income) expense	(5.8)	(6.5)
Segment Profit And Loss	342.2	355.6	901.4	910.9
Corporate and Other
Segment Reporting Information [Line Items]
Segment Profit And Loss	(18.9)	(26.8)	(59.6)	(65.1)
Residential Heating and Cooling [Member]
Segment Reporting Information [Line Items]
Net sales	937.2	912.9	2,522.8	2,643.6
Residential Heating and Cooling [Member] \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	937.2	912.9	2,522.8	2,643.6
Cost of goods sold	669.7	621.7	1,763.5	1,793.3
Selling, general and administrative	93.9	81.1	279.1	270.9
Other (income) expense	(2.1)	(5.2)	(3.8)	(11.8)
Segment Profit And Loss	175.7	215.3	484.0	591.2
Commercial Heating and Cooling
Segment Reporting Information [Line Items]
Net sales	635.3	513.9	1,730.1	1,356.7
Commercial Heating and Cooling \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	635.3	513.9	1,730.1	1,356.7
Cost of goods sold	404.7	316.9	1,099.6	859.5
Selling, general and administrative	67.8	58.0	217.4	179.5
Other (income) expense	(3.7)	(1.3)	(4.3)	(2.0)
Segment Profit And Loss	$ 166.5	$ 140.3	$ 417.4	$ 319.7