Retirement Benefits and Postemployment Benefits (Schedule of plans with accumulated benefit obiligations in excess of plan assets) (Details) - Defined Benefit Pension Plans [Member] - USD ($) $ in Millions	May 31, 2020	May 26, 2019
Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 3,512.9	$ 589.7
Accumulated benefit obligation	3,200.1	552.2
Plan assets at fair value	$ 2,569.9	$ 14.4