Retirement Benefits and Postemployment Benefits (Schedule of amounts recognized in AOCI) (Details) - USD ($) $ in Millions	May 27, 2018	May 28, 2017
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	$ (1,723.6)	$ (1,645.4)
Prior service (costs) credits	26.3	19.5
Amounts recorded in accumulated other comprehensive loss	(1,697.3)	(1,625.9)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	(1,764.1)	(1,621.4)
Prior service (costs) credits	(7.1)	(3.9)
Amounts recorded in accumulated other comprehensive loss	(1,771.2)	(1,625.3)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	44.4	(14.5)
Prior service (costs) credits	33.1	22.8
Amounts recorded in accumulated other comprehensive loss	77.5	8.3
Postemployment Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	(3.9)	(9.5)
Prior service (costs) credits	0.3	0.6
Amounts recorded in accumulated other comprehensive loss	$ (3.6)	$ (8.9)