Retirement Plans (Schedule of Amounts to be Amortized From Accumulated Other Comprehensive Income) (Details) $ in Millions	Dec. 27, 2019 USD ($)
Pension Benefits
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Amortization of net actuarial loss	$ 0.7
Amortization of prior service cost (credit)	0.1
Postretirement Benefits
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Amortization of net actuarial loss	0.0
Amortization of prior service cost (credit)	$ (2.1)