v3.26.1
PENSION AND POSTRETIREMENT BENEFITS - Components of pension and postretirement plan costs (benefits) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Feb. 22, 2026
Feb. 23, 2025
Feb. 22, 2026
Feb. 23, 2025
Pension plan        
PENSION AND POSTRETIREMENT BENEFITS        
Service cost $ 1.4 $ 1.4 $ 4.1 $ 4.1
Interest cost 22.0 34.4 66.2 101.8
Expected return on plan assets (27.8) (37.0) (83.4) (109.4)
Amortization of prior service cost (benefit) 0.4 0.4 1.2 1.2
Total pension and postretirement cost (benefit) (1.9) 1.3 (4.7) 5.0
Pension plan | Company plans        
PENSION AND POSTRETIREMENT BENEFITS        
Total pension and postretirement cost (benefit) (4.0) (0.8) (11.9) (2.3)
Pension plan | Multi employer plan        
PENSION AND POSTRETIREMENT BENEFITS        
Total pension and postretirement cost (benefit) 2.1 2.1 7.2 7.3
Other postretirement benefits plan        
PENSION AND POSTRETIREMENT BENEFITS        
Service cost     0.1 0.1
Interest cost 0.6 0.6 1.7 1.8
Amortization of prior service cost (benefit) (0.4) (0.4) (1.3) (1.3)
Recognized net actuarial gain (0.9) (1.1) (2.7) (3.4)
Total pension and postretirement cost (benefit) $ (0.7) $ (0.9) $ (2.2) $ (2.8)