Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Aug. 30, 2015	Aug. 24, 2014	May. 31, 2015
Net earnings attributable to General Mills	$ 426.6	$ 345.2
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(142.2)	(92.5)
Other fair value changes:
Securities	(0.1)	0.1
Hedge derivatives	10.3	(1.2)
Reclassification to earnings:
Hedge derivatives	0.7	3.5
Amortization of losses and prior service costs	30.9	23.5
Other comprehensive income (loss), net of tax	(100.4)	(66.6)
Total comprehensive income (loss) attributable to General Mills	317.1	310.6
General Mills [Member]
Net earnings attributable to General Mills	426.6	345.2
Other Comprehensive Income (Loss), Pretax:
Foreign currency translation	(149.9)	(60.4)
Other fair value changes:
Securities	(0.1)	0.2
Hedge derivatives	13.2	(0.8)
Reclassification to earnings:
Hedge derivatives	(1.1)	3.4
Amortization of losses and prior service costs	49.7	38.9
Other comprehensive income (loss), before tax	(88.2)	(18.7)
Other Comprehensive Income (Loss), Tax:
Foreign currency translation	0.0	0.0
Other fair value changes:
Securities	0.0	(0.1)
Hedge derivatives	(3.1)	0.2
Reclassification to earnings:
Hedge derivatives	0.6	(0.6)
Amortization of losses and prior service costs	(18.8)	(15.4)
Other comprehensive income (loss), tax	(21.3)	(15.9)
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(149.9)	(60.4)
Other fair value changes:
Securities	(0.1)	0.1
Hedge derivatives	10.1	(0.6)
Reclassification to earnings:
Hedge derivatives	(0.5)	2.8
Amortization of losses and prior service costs	30.9	23.5
Other comprehensive income (loss), net of tax	(109.5)	(34.6)
Total comprehensive income (loss) attributable to General Mills	317.1	310.6
Noncontrolling Interests [Member]
Net earnings attributable to noncontrolling interests	2.6	1.6
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	5.3	(11.6)
Other fair value changes:
Securities	0.0	0.0
Hedge derivatives	0.0	0.0
Reclassification to earnings:
Hedge derivatives	0.0	0.0
Amortization of losses and prior service costs	0.0	0.0
Other comprehensive income (loss), net of tax	5.3	(11.6)
Total comprehensive income (loss) attributable to noncontrolling interests	7.9	(10.0)
Redeemable Interests [Member]
Net earnings attributable to redeemable interests	5.9	5.6
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	2.4	(20.5)
Other fair value changes:
Securities	0.0	0.0
Hedge derivatives	0.2	(0.6)
Reclassification to earnings:
Hedge derivatives	1.2	0.7
Amortization of losses and prior service costs	0.0	0.0
Other comprehensive income (loss), net of tax	3.8	(20.4)
Total comprehensive income (loss) attributable to redeemable interests	$ 9.7	$ (14.8)	$ (122.9)