Income Taxes Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 30, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate (as a percent)	10.50%
U.S. federal statutory rate (as a percent)	21.00%	35.00%
Deferred tax assets, liquidation of foreign subsidiary	$ 17.1
Equity award excess tax benefits	6.7
Provisional tax benefit			$ 449.9
Unrecognized tax benefits, income tax penalties and interest accrued	6.4	$ 5.4
Possible reduction in unrecognized tax benefits in next twelve months	$ 13.4