v3.25.1
Post-retirement benefits - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 29, 2025
Mar. 30, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans    
—Employer service cost $ 1.0 $ 1.0
—Interest cost 6.4 6.4
—Expected return on plan assets (5.7) (6.5)
—Net amortization of prior period losses (gains) (0.3) (0.6)
Net periodic benefit cost (income) 1.4 0.3
Cash Contributions 4.4 2.6
Pensions    
Defined Benefit Plans and Other Postretirement Benefit Plans    
—Employer service cost 1.0 1.0
—Interest cost 6.1 6.1
—Expected return on plan assets (5.7) (6.5)
—Net amortization of prior period losses (gains) 0.5 0.2
Net periodic benefit cost (income) 1.9 0.8
Cash Contributions 3.5 1.6
Other post-retirement benefits    
Defined Benefit Plans and Other Postretirement Benefit Plans    
—Employer service cost 0.0 0.0
—Interest cost 0.3 0.3
—Expected return on plan assets 0.0 0.0
—Net amortization of prior period losses (gains) (0.8) (0.8)
Net periodic benefit cost (income) (0.5) (0.5)
Cash Contributions $ 0.9 $ 1.0