Retirement Benefits and Postemployment Benefits (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	May 29, 2016	May 31, 2015	May 25, 2014
Defined Benefit Plan, Information About Plan Assets
Increase in benefit plan obligation due to adoption of rates in RP-2014 MortalityTables		$ 436.7
Accumulated Benefit Obligation	$ 5,950.7	5,750.4
Defined Contribution Plan Disclosure [Line Items]
Net assets of money purchase plan	21.0	21.9
Recognized expense	$ 61.2	$ 44.0	$ 44.8
General Mills Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
ESOP number of allocated shares	6.9	7.5
Common stock held by ESOP and company stock fund	$ 711.5	$ 655.6
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 23.7	24.1
Defined Benefit Pension Plans [Member] | United States Equity Securities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	25.00%
Defined Benefit Pension Plans [Member] | International Equity Securities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	15.00%
Defined Benefit Pension Plans [Member] | Private Equities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	10.00%
Defined Benefit Pension Plans [Member] | Fixed income [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	35.00%
Defined Benefit Pension Plans [Member] | Real asset investments [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	15.00%
U.S. Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0.0	0.0	$ 0.0
Defined Benefit Plan, Information About Plan Assets
Retirement Plan Provision Termination Period	5 years
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 24.1	$ 24.1
Other Postretirement Benefit Plans [Member] | United States Equity Securities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	30.00%
Other Postretirement Benefit Plans [Member] | International Equity Securities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	20.00%
Other Postretirement Benefit Plans [Member] | Private Equities [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	10.00%
Other Postretirement Benefit Plans [Member] | Fixed income [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	30.00%
Other Postretirement Benefit Plans [Member] | Real asset investments [Member]
Defined Benefit Plan, Information About Plan Assets
Target Allocation, Percentage of Assets Equity Securities	10.00%