Retirement Benefits and Postemployment Benefits (Schedule of components of net periodic benefit expense) (Details) - USD ($) $ in Millions	12 Months Ended
	May 29, 2016	May 31, 2015	May 25, 2014
Defined Benefit Pension Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 134.6	$ 137.0	$ 133.0
Interest cost	267.8	249.2	239.5
Expected return on plan assets	(496.9)	(476.4)	(455.6)
Amortization of losses	189.8	141.7	151.0
Amortization of prior service costs (credits)	4.7	7.4	5.6
Other adjustments	5.0	15.1	0.0
Settlement or curtailment losses	13.1	18.0	0.0
Net (income) expense	118.1	92.0	73.5
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	19.0	22.4	22.7
Interest cost	44.1	46.9	50.5
Expected return on plan assets	(46.2)	(40.2)	(34.6)
Amortization of losses	6.6	4.9	15.4
Amortization of prior service costs (credits)	(5.4)	(1.6)	(3.4)
Other adjustments	2.3	3.3	0.0
Settlement or curtailment losses	(1.0)	1.3	(2.9)
Net (income) expense	19.4	37.0	47.7
Postemployment Benefit Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	7.6	7.5	7.7
Interest cost	3.9	4.3	4.1
Expected return on plan assets	0.0	0.0	0.0
Amortization of losses	0.7	0.7	0.6
Amortization of prior service costs (credits)	2.5	2.4	2.4
Other adjustments	10.7	9.5	3.7
Settlement or curtailment losses	0.0	0.0	0.0
Net (income) expense	$ 25.4	$ 24.4	$ 18.5