Reportable Business Segments (Key Financial Information by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Net sales	$ 1,426.8	$ 1,498.1	$ 4,000.3	$ 3,996.3
Cost of Goods Sold	958.2	1,009.7	2,680.7	2,679.7
Selling, general and administrative	161.6	184.4	506.2	523.6
Other (income) expense	(3.2)	0.7	(6.4)	4.4
Segment Profit And Loss	310.2	303.3	819.8	788.6
Segment Reporting, Reconciling Item, Corporate Nonsegment
Segment Reporting Information [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of Goods Sold	1.1	0.6	1.9	1.1
Selling, general and administrative	22.4	25.0	55.8	63.2
Other (income) expense	3.2	3.5	7.4	12.3
Segment Profit And Loss	(26.7)	(29.1)	(65.1)	(76.6)
Residential Heating and Cooling [Member]
Segment Reporting Information [Line Items]
Net sales	912.9	1,032.8	2,643.6	2,689.7
Residential Heating and Cooling [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net sales	912.9	1,032.8	2,643.6	2,689.7
Cost of Goods Sold	634.0	706.6	1,809.5	1,833.8
Selling, general and administrative	81.2	100.4	271.0	292.5
Other (income) expense	(5.2)	(0.7)	(11.8)	(3.7)
Segment Profit And Loss	202.9	226.5	574.9	567.1
Commercial Heating and Cooling
Segment Reporting Information [Line Items]
Net sales	513.9	465.3	1,356.7	1,306.6
Commercial Heating and Cooling | Operating Segments
Segment Reporting Information [Line Items]
Net sales	513.9	465.3	1,356.7	1,306.6
Cost of Goods Sold	323.1	302.5	869.3	844.8
Selling, general and administrative	58.0	59.0	179.4	167.9
Other (income) expense	(1.2)	(2.1)	(2.0)	(4.2)
Segment Profit And Loss	$ 134.0	$ 105.9	$ 310.0	$ 298.1