Leases - Lease expense (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019
Leases [Abstract]
Operating lease cost	$ 49.0	$ 47.7
Short-term lease cost	8.0	3.0
Finance lease cost
Amortization of right-of-use assets	11.7	4.5
Interest on lease liabilities	3.5	1.2
Total finance lease cost	15.2	5.7
Sublease income	0.7	0.8
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	52.2	47.2
Operating cash flows from finance leases	3.6	1.1
Financing cash flows from finance leases	10.5	3.8
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	29.5	25.0
Finance leases	$ 52.2	$ 28.6