PENSION AND POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Nov. 26, 2017	May 26, 2019	May 27, 2018	May 28, 2017	May 29, 2016	Sep. 30, 2017	Aug. 27, 2017	Dec. 31, 2016	Nov. 09, 2016
Defined Benefit Plan Disclosure [Line Items]
Expense related to expected incurrence of certain multi-employer plan withdrawal costs		$ 0.3	$ 0.6	$ 4.0
Fair value of certain investments		51.0
Fair value of funds which have imposed such gates		4.2
Additional expense related to expected incurrence of certain withdrawal costs		0.3	0.6	4.0
Expense related to defined contribution plans		$ 39.9	$ 24.5	18.0
Generally less than
Defined Benefit Plan Disclosure [Line Items]
Maximum allowable funding percentage to be in critical status		65.00%
Maximum allowable funding percentage to be in endangered status		80.00%
Generally at least
Defined Benefit Plan Disclosure [Line Items]
Minimum required funding percentage to be in the green zone		80.00%
Percentage of plan's total contribution under Forms 5500 (more than)		5.00%
Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Unfunded commitments for additional investments		$ 48.3
Natural resources funds
Defined Benefit Plan Disclosure [Line Items]
Unfunded commitments for additional investments		$ 17.0
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)		90.00%
Return seeking securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)		10.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Effective discount rate assumption		3.88%	4.14%					4.11%
Decrease to underfunded status of the pension plans		$ 0.0	$ 79.5
Charge reflecting year-end write-off of actuarial losses	$ 3.4		5.1	3.4	$ 1.2
Accumulated benefit obligation		3,700.0	3,400.0
Lump-sum settlement payments		0.0	10.2	287.5
Settlement charge		0.0	1.3	13.8
Benefit to accumulated other comprehensive income (loss)				62.2
Pre-tax reduction in total pension benefit cost associated with change in accounting estimate		(16.4)	$ (49.0)	(0.9)
Anticipated contributions to plans in fiscal 2020		$ 14.2
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Effective discount rate assumption		3.48%	3.81%
Decrease to underfunded status of the pension plans		$ 0.6	$ 0.0
Lump-sum settlement payments		0.5	0.0
Settlement charge		(1.0)	0.0	0.0
Pre-tax reduction in total pension benefit cost associated with change in accounting estimate		(1.3)	$ 0.7	(1.2)
Anticipated contributions to plans in fiscal 2020		$ 10.8
Spinoff | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Effective discount rate assumption					3.86%	3.78%	3.90%		4.04%
Decrease to underfunded status of the pension plans	43.5			66.0
Pension curtailment gain (charge) within other comprehensive income (loss)	$ (0.7)			19.5
Discontinued operations
Defined Benefit Plan Disclosure [Line Items]
Expense related to expected incurrence of certain multi-employer plan withdrawal costs				2.1
Restructuring activities
Defined Benefit Plan Disclosure [Line Items]
Expense related to expected incurrence of certain multi-employer plan withdrawal costs				1.9
Change in Assumptions for Defined Benefit Plans | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pre-tax reduction in total pension benefit cost associated with change in accounting estimate				$ 27.0