Comprehensive Income (Components Of Accumulated Other Comprehensive Income, Net Of Related Tax) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Accumulated foreign currency translation adjustments	$ (127.6)	$ (216.8)
Net unrealized loss on short-term investments	(0.2)
Net unrealized actuarial losses	(3.4)	(3.1)
Total accumulated other comprehensive income	$ (131.2)	$ (219.9)