Retirement Benefits and Postemployment Benefits (Schedule of components of net periodic benefit expense) (Details) - USD ($) $ in Millions	12 Months Ended
	May 30, 2021	May 31, 2020	May 26, 2019
Defined Benefit Pension Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 104.4	$ 92.7	$ 94.6
Interest cost	192.1	230.5	248.0
Expected return on plan assets	(420.9)	(449.9)	(445.8)
Amortization of losses (gains)	108.3	106.0	109.8
Amortization of prior service costs (credits)	1.3	1.6	1.5
Other adjustments	0.0	0.0	0.0
Settlement or curtailment losses	14.9	0.0	0.3
Net expense (income)	0.1	(19.1)	8.4
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	8.5	9.4	9.9
Interest cost	18.0	27.1	33.1
Expected return on plan assets	(34.7)	(42.1)	(40.4)
Amortization of losses (gains)	(5.1)	(2.1)	0.6
Amortization of prior service costs (credits)	(5.5)	(5.5)	(5.5)
Other adjustments	0.0	0.0	0.0
Settlement or curtailment losses	0.0	0.0	0.0
Net expense (income)	(18.8)	(13.2)	(2.3)
Postemployment Benefit Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	9.3	8.3	7.6
Interest cost	1.7	2.6	3.0
Expected return on plan assets	0.0	0.0	0.0
Amortization of losses (gains)	2.6	0.4	0.1
Amortization of prior service costs (credits)	0.9	0.9	0.7
Other adjustments	8.4	17.7	6.7
Settlement or curtailment losses	0.0	0.0	0.0
Net expense (income)	$ 22.9	$ 29.9	$ 18.1