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. 25, 2018	Feb. 26, 2017	Feb. 25, 2018	Feb. 26, 2017
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25.7	$ 29.9	$ 77.1	$ 89.9
Interest cost	54.5	54.1	163.4	162.4
Expected return on plan assets	(120.1)	(121.6)	(360.1)	(365.1)
Amortization of losses	44.6	47.2	132.8	142.2
Amortization of prior service costs (credits)	0.4	0.6	1.4	1.8
Other adjustments	0.0	0.0	0.0	2.1
Settlement or curtailment losses	0.0	0.0	0.0	4.4
Net expense (income)	5.1	10.2	14.6	37.7
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.9	3.2	8.7	9.4
Interest cost	7.6	8.2	22.8	24.2
Expected return on plan assets	(13.0)	(12.1)	(39.1)	(36.3)
Amortization of losses	0.2	0.6	0.6	1.9
Amortization of prior service costs (credits)	(1.3)	(1.5)	(4.0)	(4.1)
Other adjustments	0.0	0.0	0.0	1.3
Settlement or curtailment losses	0.0	0.0	0.0	0.7
Net expense (income)	(3.6)	(1.6)	(11.0)	(2.9)
Postemployment Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	2.2	6.4	6.6
Interest cost	0.6	0.7	1.7	2.1
Expected return on plan assets	0.0	0.0	0.0	0.0
Amortization of losses	0.2	0.4	0.6	1.3
Amortization of prior service costs (credits)	0.2	0.2	0.5	0.5
Other adjustments	0.4	3.4	7.2	10.2
Settlement or curtailment losses	0.0	0.0	0.0	0.0
Net expense (income)	$ 3.5	$ 6.9	$ 16.4	$ 20.7