Retirement Benefits and Postemployment Benefits (Schedule of amounts recognized in AOCI) (Details) - USD ($) $ in Millions	May 31, 2020	May 26, 2019
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	$ (2,022.5)	$ (1,880.5)
Prior service (costs) credits	9.7	14.4
Amounts recorded in accumulated other comprehensive loss	(2,012.8)	(1,866.1)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	(2,136.6)	(1,961.6)
Prior service (costs) credits	(6.0)	(5.9)
Amounts recorded in accumulated other comprehensive loss	(2,142.6)	(1,967.5)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	129.5	81.0
Prior service (costs) credits	21.0	26.3
Amounts recorded in accumulated other comprehensive loss	150.5	107.3
Postemployment Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	(15.4)	0.1
Prior service (costs) credits	(5.3)	(6.0)
Amounts recorded in accumulated other comprehensive loss	$ (20.7)	$ (5.9)