Retirement and Postemployment Benefits (Schedule of components of net pension, other postretirement, and postemployment (income) expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2016	Feb. 22, 2015	Feb. 28, 2016	Feb. 22, 2015
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 33.5	$ 34.3	$ 100.9	$ 103.1
Interest cost	66.9	62.3	200.9	187.2
Expected return on plan assets	(124.2)	(119.1)	(372.8)	(357.6)
Amortization of losses	47.6	35.4	142.3	106.2
Amortization of prior service costs (credits)	1.2	1.9	3.6	5.6
Other adjustments	0.1	10.6	5.1	15.0
Settlement or curtailment losses	0.0	7.9	11.3	18.0
Net expense	25.1	33.3	91.3	77.5
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4.7	5.6	14.2	16.8
Interest cost	11.0	11.8	33.0	35.3
Expected return on plan assets	(11.5)	(10.0)	(34.6)	(30.1)
Amortization of losses	1.7	1.2	5.0	3.7
Amortization of prior service costs (credits)	(1.4)	(0.4)	(4.1)	(1.2)
Other adjustments	0.0	3.1	2.4	3.4
Settlement or curtailment losses	0.0	0.5	0.2	1.3
Net expense	4.5	11.8	16.1	29.2
Postemployment Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.9	1.8	5.7	5.6
Interest cost	1.0	1.1	3.0	3.2
Expected return on plan assets	0.0	0.0	0.0	0.0
Amortization of losses	0.1	0.1	0.5	0.5
Amortization of prior service costs (credits)	0.6	0.6	1.8	1.8
Other adjustments	2.8	3.2	9.3	9.5
Settlement or curtailment losses	0.0	0.0	0.0	0.0
Net expense	$ 6.4	$ 6.8	$ 20.3	$ 20.6