Retirement Plans (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	Nov. 30, 2019	Feb. 23, 2020	Nov. 24, 2019	Feb. 24, 2019	Feb. 23, 2020	Feb. 24, 2019
Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost		$ 0.0		$ 2.4	$ 3.2	$ 7.0
Expected return on plan assets		0.0		(2.8)	(4.0)	(8.4)
Pension settlement expense	$ 147.1	0.0		0.0	147.1	0.0
Recognized net actuarial loss		0.1		0.6	1.8	1.9
Net periodic benefit cost		0.1		0.2	148.1	0.5
Employer contributions			$ 12.2
Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost		0.2		0.2	0.5	0.6
Amortization of unrecognized prior service credit		(1.2)		(1.2)	(3.5)	(3.6)
Recognized net actuarial loss		0.4		0.4	1.1	1.2
Net periodic benefit cost		$ (0.6)		$ (0.6)	$ (1.9)	$ (1.8)