Investments (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Apr. 01, 2017	Apr. 02, 2016	Dec. 31, 2016
Unrealized Gain (Loss) on Investments [Abstract]
Impairment of investments			$ 1.8
Gain on sale of investments	$ 1.6		1.0
Loss from equity method investments	0.1	$ (2.4)
Transfer from investments		15.5
Unrealized gain (loss) on investments		$ 8.7
Estimated fair value of equity securities
Unrealized Gain (Loss) on Investments [Abstract]
Equity securities, at cost less impairments	15.5		16.5
Gross unrealized gains	7.3		21.7
Estimated fair value of equity securities	22.8		38.2
Other non-current assets
Unrealized Gain (Loss) on Investments [Abstract]
Cost method investments	6.9
Equity method investments	$ 4.8		$ 4.6