Retirement Benefits and Postemployment Benefits (Schedule of summarized financial information about benefit plans) (Details) - USD ($) $ in Millions	12 Months Ended
	May 28, 2017	May 29, 2016	May 31, 2015
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets Roll Forward [Abstract]
Fair value at beginning of year	$ 5,539.9	$ 5,758.5
Actual return on assets	645.6	36.3
Employer contributions	25.4	23.7
Plan participant contributions	8.8	5.7
Benefits payments	(282.2)	(277.5)
Foreign currency	(12.3)	(6.8)
Fair value at end of year	5,925.2	5,539.9	$ 5,758.5
Defined Benefit Plan, Change in Projected Benefit Obligation Roll Forward [Abstract]
Benefit obligation at beginning of year	6,448.5	6,252.1
Service cost	119.7	134.6	137.0
Interest cost	216.5	267.8	249.2
Plan amendment	(130.9)	0.9
Curtailment/other	1.9	7.1
Plan participant contributions	8.8	5.7
Medicare Part D reimbursements	0.0	0.0
Actuarial loss (gain)	88.5	65.2
Benefits payments	(282.6)	(278.0)
Foreign currency	(11.8)	(6.9)
Projected benefit obligation at end of year	6,458.6	6,448.5	6,252.1
Plan assets less than benefit obligation as of fiscal year end	(533.4)	(908.6)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets Roll Forward [Abstract]
Fair value at beginning of year	602.4	582.8
Actual return on assets	75.2	(0.1)
Employer contributions	20.1	24.1
Plan participant contributions	15.2	14.1
Benefits payments	(18.1)	(18.5)
Foreign currency	0.0	0.0
Fair value at end of year	694.8	602.4	582.8
Defined Benefit Plan, Change in Projected Benefit Obligation Roll Forward [Abstract]
Benefit obligation at beginning of year	1,028.9	1,079.6
Service cost	12.5	19.0	22.4
Interest cost	32.2	44.1	46.9
Plan amendment	0.0	0.0
Curtailment/other	(0.3)	0.5
Plan participant contributions	15.2	14.1
Medicare Part D reimbursements	3.4	3.5
Actuarial loss (gain)	(77.6)	(64.5)
Benefits payments	(63.3)	(66.4)
Foreign currency	0.4	(1.0)
Projected benefit obligation at end of year	951.4	1,028.9	1,079.6
Plan assets less than benefit obligation as of fiscal year end	(256.6)	(426.5)
Postemployment Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets Roll Forward [Abstract]
Plan participant contributions	0.0	0.0
Defined Benefit Plan, Change in Projected Benefit Obligation Roll Forward [Abstract]
Benefit obligation at beginning of year	164.1	146.6
Service cost	8.8	7.6	7.5
Interest cost	2.6	3.9	4.3
Plan amendment	0.0	1.1
Curtailment/other	1.3	10.7
Plan participant contributions	0.0	0.0
Medicare Part D reimbursements	0.0	0.0
Actuarial loss (gain)	(7.4)	11.2
Benefits payments	(34.7)	(16.9)
Foreign currency	(0.2)	(0.1)
Projected benefit obligation at end of year	134.5	164.1	$ 146.6
Plan assets less than benefit obligation as of fiscal year end	$ (134.5)	$ (164.1)