Goodwill and other intangible assets - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2026	Jan. 01, 2026	Dec. 31, 2025
Intangible Asset, Goodwill and Other [Abstract]
Goodwill, net (see note 7)	$ 4,925.9	$ 4,986.9	$ 4,986.9

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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