Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jun. 27, 2015	Jul. 02, 2016	Dec. 31, 2015	Jun. 27, 2015	Apr. 02, 2016
Schedule of Equity Method Investments [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	$ 1.7
Loss from equity method investments	(1.6)	$ (3.3)		$ (3.9)	$ (3.6)
Equity Method Investment, Other than Temporary Impairment	22.3
Unrealized Gain (Loss) on Investments [Abstract]
Equity securities, at cost less impairments	20.2		$ 20.2	6.4
Gross unrealized gains	19.8		19.8	9.3
Gross unrealized losses	0.0		0.0	(0.8)
Transfer from investments			15.5
Unrealized gain (loss) on investments			8.7
Available-for-sale securities [Member]
Unrealized Gain (Loss) on Investments [Abstract]
Estimated fair value of equity securities	40.0		40.0	14.9
Other non-current assets [Member]
Schedule of Equity Method Investments [Line Items]
Cost method investments	$ 7.0		$ 7.0	6.9
Equity method investments				$ 45.5		$ 4.8