Derivative financial instruments - OCI Movement (Details) - Interest Rate Contract - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023
Movement recognized in OCI in relation to:
—Fair value gain (loss) on cash flow hedges	$ (17.0)	$ 11.4	$ 0.4	$ 25.0
—Amortization to net income of prior period fair value losses	0.0	0.0	0.0	8.9
—Deferred OCI reclassified to net income	(9.0)	(8.9)	(27.0)	(24.0)
Total movement	$ (26.0)	$ 2.5	$ (26.6)	$ 9.9