PENSION AND POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended		12 Months Ended
	Jan. 31, 2020	Feb. 28, 2021	Feb. 23, 2020	Aug. 25, 2019	Feb. 28, 2021	Feb. 23, 2020	May 30, 2021	Dec. 31, 2019	Nov. 24, 2019	May 27, 2019
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effective discount rate assumption	3.86%		2.96%			2.96%		3.37%	3.89%
Pension curtailment loss within other comprehensive income (loss)	$ 0.2	$ 0.0	$ 0.2		$ 0.0	$ 0.8
Increase to underfunded status of the pension plans	$ 4.3
Lump-sum settlement payment			154.6
Settlement gain		0.0	2.1		0.0	$ 2.1
Benefit to other comprehensive income (loss)			$ 79.8
Employer contributions to pension and other postretirement plans		3.0			23.7
Anticipated further contributions for the remainder of fiscal 2021		8.5			8.5
Pension Benefits | Scenario, Forecast
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Weighted average discount rate for service costs							3.35%
Weighted average discount rate for interest costs							2.30%
Pension Benefits | Facility Closing
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effective discount rate assumption				3.13%						3.90%
Pension curtailment loss within other comprehensive income (loss)				$ 0.6
Increase to underfunded status of the pension plans				$ 12.3
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Employer contributions to pension and other postretirement plans		2.0			6.1
Anticipated further contributions for the remainder of fiscal 2021		$ 3.9			$ 3.9