PENSION AND POSTRETIREMENT BENEFITS - Components of pension and postretirement plan costs (benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	May 25, 2025	May 26, 2024	May 28, 2023
Pension plan
PENSION AND POSTRETIREMENT BENEFITS
Projected benefit obligation	$ 89.8	$ 95.9
Accumulated benefit obligation	89.8	95.9
Service cost	5.5	5.8	$ 6.5
Interest cost	136.1	144.7	124.0
Expected return on plan assets	(146.3)	(141.3)	(145.9)
Amortization of prior service cost (benefit)	1.6	1.6	1.4
Recognized net actuarial gain	(3.5)	(12.5)	0.1
Settlement loss	(13.0)	1.1
Total pension and postretirement cost (benefit)	(10.1)	8.4	(4.7)
Pension plan | Company plans
PENSION AND POSTRETIREMENT BENEFITS
Total pension and postretirement cost (benefit)	(19.6)	(0.6)	(13.9)
Pension plan | Multi employer plan
PENSION AND POSTRETIREMENT BENEFITS
Total pension and postretirement cost (benefit)	9.5	9.0	9.2
Other postretirement benefits plan
PENSION AND POSTRETIREMENT BENEFITS
Service cost	0.1	0.1	0.1
Interest cost	2.4	2.5	2.3
Amortization of prior service cost (benefit)	(1.7)	(1.7)	(1.7)
Recognized net actuarial gain	(1.5)	(4.7)	(4.4)
Total pension and postretirement cost (benefit)	(0.7)	(3.8)	(3.7)
Other postretirement benefits plan | Company plans
PENSION AND POSTRETIREMENT BENEFITS
Total pension and postretirement cost (benefit)	$ (0.7)	$ (3.8)	$ (3.7)