PENSION AND POSTRETIREMENT BENEFITS - Schedule of Changes in Benefit Obligations and Plan Assets (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 31, 2020	Feb. 23, 2020	May 30, 2021	May 31, 2020	May 26, 2019
Change in Plan Assets
Fair value of plan assets at beginning of year			$ 3,820.4
Fair value of plan assets at end of year			3,848.8	$ 3,820.4
Pension Plans
Change in Benefit Obligation
Benefit obligation at beginning of year			3,872.5	3,733.2
Service cost			11.6	11.5	$ 10.9
Interest cost			86.8	118.4	132.6
Actuarial loss (gain)			(37.4)	411.6
Plan settlements				(201.7)
Curtailments	$ 4.3			(0.8)
Benefits paid			(196.8)	(199.3)
Currency			2.5	(0.4)
Benefit obligation at end of year			3,739.2	3,872.5	3,733.2
Change in Plan Assets
Fair value of plan assets at beginning of year			3,820.4	3,601.5
Actual return on plan assets			194.6	557.5
Employer contributions			27.6	17.5
Plan settlements		$ (154.6)		(156.3)
Benefits paid			(196.8)	(199.3)
Currency			3.0	(0.5)
Fair value of plan assets at end of year			3,848.8	3,820.4	3,601.5
Postretirement Plans
Change in Benefit Obligation
Benefit obligation at beginning of year			89.8	91.2
Service cost			0.2	0.1	0.1
Interest cost			1.5	2.6	3.8
Actuarial loss (gain)			(2.3)	3.0
Plan settlements			(0.3)	(0.1)
Benefits paid			(8.5)	(6.9)
Currency			1.1	(0.1)
Benefit obligation at end of year			81.5	89.8	91.2
Change in Plan Assets
Fair value of plan assets at beginning of year			3.4	3.4
Actual return on plan assets			0.2	0.1
Employer contributions			8.5	6.9
Plan settlements			(0.3)	(0.1)
Benefits paid			(8.5)	(6.9)
Fair value of plan assets at end of year			$ 3.3	$ 3.4	$ 3.4