Segment financial information - reconciliation of reconciliation of net income (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Jun. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Reconciliation of Adjusted EBITDA from net income or loss
Adjusted Operating Income	$ 227.6	$ 237.3		$ 643.3	$ 732.3
Amortization	(75.5)	(76.1)		(227.1)	(225.5)
Reserve for certain legal matters, net	(1.3)	(1.6)		(4.7)	(5.2)
Other	(3.2)	(7.5)		(3.5)	(11.7)
Impairment charges	0.0	(785.0)	$ (785.0)	0.0	(785.0)
Interest expense, net	(39.9)	(44.2)		(122.2)	(129.8)
Loss on extinguishment of debt	0.8	0.2		2.0	0.2
Other (expense) income, net	(0.8)	3.7		(1.9)	(19.5)
Income (loss) before income taxes	98.0	(689.5)		234.7	(522.1)
Severance costs					6.1
Goodwill, impairment loss		785.0
Business Exit Costs And Employee Severance
Reconciliation of Adjusted EBITDA from net income or loss
Restructuring charges	(8.1)	(2.2)		(47.2)	(28.0)
External Advisors
Reconciliation of Adjusted EBITDA from net income or loss
Restructuring charges	$ 0.0	$ (13.7)		$ 0.0	$ (49.5)