Related party transactions - Transactions with Non-Gates entities (Details) - Non-Gates entities controlled by non-controlling shareholders - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018	Dec. 29, 2018
Related Party Transaction [Line Items]
Sales	$ 12.4	$ 15.7	$ 25.8	$ 31.7
Purchases	(4.9)	$ (5.2)	(10.3)	$ (10.5)
Receivables	4.6		4.6		$ 0.6
Payables	$ (4.0)		$ (4.0)		$ (0.3)

For an unclassified balance sheet, amounts due from related parties including affiliates, employees, joint ventures, officers and stockholders, immediate families thereof, and pension funds.

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Carrying amount as of the balance sheet date of obligations due all related parties.

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