Employee Benefits (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jul. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Contribution Plan, Cost		$ 2.5	$ 2.7	$ 5.3	$ 5.4
Retirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		0.9	0.9	1.8	1.8
Interest cost		1.1	1.1	2.2	2.3
Expected return on plan assets		(2.0)	(2.0)	(4.0)	(3.9)
Amortization of unrecognized net loss		0.4	0.5	0.8	0.9
Settlement charge		1.6	0.6	2.2	1.1
Net periodic benefit cost		2.0	1.1	3.0	2.2
PBOP
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		0.1	0.0	0.1	0.1
Interest cost		0.3	0.4	0.7	0.8
Expected return on plan assets		(1.2)	(1.1)	(2.3)	(2.2)
Amortization of unrecognized net loss		0.0	0.0	0.0	0.0
Settlement charge		0.0	0.0	0.0	0.0
Net periodic benefit cost		$ (0.8)	$ (0.7)	$ (1.5)	$ (1.3)
Subsequent Event
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0.0
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 3.0