Employee Benefit Plans - Schedule of Components of Net Pension and Post-retirement Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 08, 2018	Sep. 09, 2017	Sep. 08, 2018	Sep. 09, 2017
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated return on plan assets	$ (26.0)	$ (27.6)	$ (60.6)	$ (64.4)
Service cost	12.1	11.5	28.2	26.8
Interest cost	19.8	20.4	46.2	47.5
Amortization of prior service cost	0.0	0.0	0.0	0.1
Amortization of net actuarial (gain) loss	(1.5)	0.1	(3.4)	0.2
Net expense	4.4	4.4	10.4	10.2
Other post-retirement benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated return on plan assets	0.0	0.0	0.0	0.0
Service cost	0.2	0.2	0.5	0.5
Interest cost	0.1	0.2	0.3	0.5
Amortization of prior service cost	0.9	0.9	2.0	2.0
Amortization of net actuarial (gain) loss	0.0	0.0	(0.1)	0.0
Net expense	$ 1.2	$ 1.3	$ 2.7	$ 3.0