Retirement Benefits and Postemployment Benefits (Schedule of summarized financial information about benefit plans) (Details) - USD ($) $ in Millions	12 Months Ended
	May 29, 2016	May 31, 2015	May 25, 2014
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets Roll Forward [Abstract]
Fair value at beginning of year	$ 5,758.5	$ 5,611.8
Actual return on assets	36.3	373.6
Employer contributions	23.7	24.1
Plan participant contributions	5.7	10.3
Benefits payments	(277.5)	(244.9)
Foreign currency	(6.8)	(16.4)
Fair value at end of year	5,539.9	5,758.5	$ 5,611.8
Defined Benefit Plan, Change in Projected Benefit Obligation Roll Forward [Abstract]
Benefit obligation at beginning of year	6,252.1	5,618.0
Service cost	134.6	137.0	133.0
Interest cost	267.8	249.2	239.5
Plan amendment	0.9	1.9
Curtailment/other	7.1	19.9
Plan participant contributions	5.7	10.3
Medicare Part D reimbursements	0.0	0.0
Actuarial loss (gain)	65.2	479.7
Benefits payments	(278.0)	(245.5)
Foreign currency	(6.9)	(18.4)
Projected benefit obligation at end of year	6,448.5	6,252.1	5,618.0
Plan assets less than benefit obligation as of fiscal year end	(908.6)	(493.6)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets Roll Forward [Abstract]
Fair value at beginning of year	582.8	517.3
Actual return on assets	(0.1)	44.0
Employer contributions	24.1	24.1
Plan participant contributions	14.1	13.6
Benefits payments	(18.5)	(16.2)
Foreign currency	0.0	0.0
Fair value at end of year	602.4	582.8	517.3
Defined Benefit Plan, Change in Projected Benefit Obligation Roll Forward [Abstract]
Benefit obligation at beginning of year	1,079.6	1,074.8
Service cost	19.0	22.4	22.7
Interest cost	44.1	46.9	50.5
Plan amendment	0.0	(42.4)
Curtailment/other	0.5	3.4
Plan participant contributions	14.1	13.6
Medicare Part D reimbursements	3.5	3.2
Actuarial loss (gain)	(64.5)	23.5
Benefits payments	(66.4)	(62.8)
Foreign currency	(1.0)	(3.0)
Projected benefit obligation at end of year	1,028.9	1,079.6	1,074.8
Plan assets less than benefit obligation as of fiscal year end	(426.5)	(496.8)
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	146.6	145.3
Service cost	7.6	7.5	7.7
Interest cost	3.9	4.3	4.1
Plan amendment	1.1	0.0
Curtailment/other	10.7	9.5
Plan participant contributions	0.0	0.0
Medicare Part D reimbursements	0.0	0.0
Actuarial loss (gain)	11.2	(0.4)
Benefits payments	(16.9)	(19.1)
Foreign currency	(0.1)	(0.5)
Projected benefit obligation at end of year	164.1	146.6	$ 145.3
Plan assets less than benefit obligation as of fiscal year end	$ (164.1)	$ (146.6)