Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income by Component, Net of Tax (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 18.1	$ 24.9
Unrealized Gains and Losses on Investment			44.8	13.6
Pension Liability Adjustments			(1.5)	(3.1)
Total			61.4	35.4
Other comprehensive income (loss), Foreign Currency Translation Adjustments	1.8	(2.4)	2.2	(9.4)
Other comprehensive income (loss), Unrealized gains and losses on Investment	10.6	11.5	10.5	23.8
Other comprehensive income (loss), pension liability adjustments			0	0
Other comprehensive income	12.4	9.1	12.7	14.4
Ending balance, foreign currency translation adjustments	20.3	15.5	20.3	15.5
Ending balance, unrealized gains and losses on investment	55.3	37.4	55.3	37.4
Ending balance, pension liability adjustments	(1.5)	(3.1)	(1.5)	(3.1)
Ending balance	$ 74.1	$ 49.8	$ 74.1	$ 49.8