Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Other than temporary impairment losses, investments, portion recognized in earnings, net, available-for-sale securities			$ 1.8
Loss from equity method investments	$ 0.1	$ (4.1)	(3.8)	$ (7.7)
Equity method investment, other than temporary impairment			22.3
Unrealized Gain (Loss) on Investments [Abstract]
Equity securities, at cost less impairments	20.1		20.1		$ 6.4
Gross unrealized gains	32.9		32.9		9.3
Gross unrealized losses	0.0		0.0		(0.8)
Transfer from investments			15.5
Unrealized gain (loss) on investments			8.7
Estimated fair value of equity securities
Unrealized Gain (Loss) on Investments [Abstract]
Estimated fair value of equity securities	53.0		53.0		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	$ 4.9		$ 4.9		$ 45.5