Summary of Significant Accounting Policies - Impact on Financial Position from Adoption of ASC 606 (Details) - USD ($) $ in Millions	Sep. 29, 2018	Apr. 01, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	$ 339.9	$ 294.3	$ 290.5
Accrued expenses and other current liabilities	345.8	291.0	295.6
Deferred tax liabilities	181.5	188.0	186.3
Retained earnings	$ 4,487.7	4,158.7	4,152.0
As Reported under ASC 605
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net			290.5
Accrued expenses and other current liabilities			295.6
Deferred tax liabilities			186.3
Retained earnings			$ 4,152.0
ASU 2014-09 | ASC 606 Adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net		3.8
Accrued expenses and other current liabilities		(4.6)
Deferred tax liabilities		1.7
Retained earnings		6.7
ASU 2014-09 | Product licensing revenue | ASC 606 Adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net		3.5
ASU 2014-09 | Guaranteed advertising minimums | ASC 606 Adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net		$ 0.3