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 | ||