Sales - Contract liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 27, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue - current	$ 423.5	$ 410.1
Deferred revenue - noncurrent	95.1	99.2
Total contract liabilities	518.6	$ 509.3
Contract liabilities, revenue recognized	$ 126.0