Segment financial information - product lines (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation by product line
Net sales	$ 1,698.3	$ 1,623.8	$ 4,972.0	$ 4,888.6
Proprietary
Disaggregation by product line
Net sales	907.9	855.6	2,621.6	2,579.1
Third-party
Disaggregation by product line
Net sales	$ 790.4	$ 768.2	$ 2,350.4	$ 2,309.5