Segment financial information - product lines (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation by product line
Net sales	$ 6,552.2	$ 6,783.6	$ 6,967.2
Proprietary
Disaggregation by product line
Net sales	3,448.9	3,615.1	3,720.2
Third-party
Disaggregation by product line
Net sales	$ 3,103.3	$ 3,168.5	$ 3,247.0

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details