Investments (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 31, 2017
ASU 2016-01
Schedule of Equity Method Investments [Line Items]
Reclassification from OCI						$ 1.0
Other expense, net
Schedule of Equity Method Investments [Line Items]
Equity securities, fair value method, other expense (income)		$ 6.3	$ 0.0	$ 10.6	$ 0.0
Equity securities, equity method, other expense (income)		(0.9)	$ (0.2)	(0.7)	$ (0.3)
Prepaid expenses and other current assets
Schedule of Equity Method Investments [Line Items]
Equity securities, fair value method		8.1		8.1
Equity securities, fair value method, previous year	[1]					17.0
Other non-current assets
Schedule of Equity Method Investments [Line Items]
Equity securities, fair value method	[2]	4.6		4.6
Equity securities, fair value method, previous year	[1]					6.3
Equity securities, equity method, other non-current assets		13.1		$ 13.1		4.9	[1]
Retained Earnings | ASU 2016-01
Schedule of Equity Method Investments [Line Items]
Reclassification to retained earnings						$ 1.4
Zibo Xinhua
Schedule of Equity Method Investments [Line Items]
Increase in investment in Zibo Xinhua		$ 7.5

[1] The December 31, 2017 balances presented reflect historical recognition and measurement investment categories existing prior to the adoption of ASU 2016-01, which include available for sale and cost method securities.

[2] The June 30, 2018 equity securities are measured at fair value using the Net Asset Value practical expedient.