Retirement Benefits and Postemployment Benefits (Schedule of plans with accumulated benefit obiligations in excess of plan assets) (Details) - USD ($) $ in Millions	May 28, 2017	May 29, 2016
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 610.1	$ 5,490.3
Accumulated benefit obligation	542.3	4,998.3
Plan assets at fair value	51.9	4,498.5
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets [Abstract]
Projected benefit obligation	5.5	0.0
Accumulated benefit obligation	947.9	1,024.7
Plan assets at fair value	694.8	602.4
Postemployment Benefit Plans [Member]
Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets [Abstract]
Projected benefit obligation	4.4	4.8
Accumulated benefit obligation	130.1	159.3
Plan assets at fair value	$ 0.0	$ 0.0