Retirement Benefits and Postemployment Benefits (Schedule of amounts recognized in AOCI) (Details) (USD $) In Millions, unless otherwise specified	May 26, 2013	May 27, 2012
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (1,801.5)	$ (1,945.9)
Prior service costs (credits)	(7.8)	(7.2)
Amounts recorded in accumulated other comprehensive loss	(1,809.3)	(1,953.1)
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(1,625.1)	(1,714.1)
Prior service costs (credits)	(18.5)	(22.0)
Amounts recorded in accumulated other comprehensive loss	(1,643.6)	(1,736.1)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(168.2)	(215.0)
Prior service costs (credits)	16.6	19.0
Amounts recorded in accumulated other comprehensive loss	(151.6)	(196.0)
Postemployment Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(8.2)	(16.8)
Prior service costs (credits)	(5.9)	(4.2)
Amounts recorded in accumulated other comprehensive loss	$ (14.1)	$ (21.0)