Retirement Benefits and Postemployment Benefits (Schedule of assumptions used to determine net periodic expense) (Details)	12 Months Ended
	May 28, 2017		May 29, 2016	May 31, 2015
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term rate of return on plan assets	8.25%
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.19%	[1]	4.38%	4.54%
Service cost effective rate	4.57%	[1]	0.00%	0.00%
Interest cost effective rate	3.44%	[1]	0.00%	0.00%
Rate of salary increases	4.28%	[1]	4.31%	4.44%
Expected long-term rate of return on plan assets	8.17%	[1]	8.53%	8.53%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.97%	[1]	4.20%	4.51%
Service cost effective rate	4.42%	[1]	0.00%	0.00%
Interest cost effective rate	3.17%	[1]	0.00%	0.00%
Rate of salary increases	0.00%	[1]	0.00%	0.00%
Expected long-term rate of return on plan assets	7.85%	[1]	8.14%	8.13%
Postemployment Benefit Plans [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	2.94%	[1]	3.55%	3.82%
Service cost effective rate	3.55%	[1]	0.00%	0.00%
Interest cost effective rate	2.67%	[1]	0.00%	0.00%
Rate of salary increases	4.35%	[1]	4.36%	4.44%
Expected long-term rate of return on plan assets	0.00%	[1]	0.00%	0.00%

[1] (a) Beginning in fiscal 2017, we adopted the full yield curve method.