Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Aug. 25, 2013	Aug. 26, 2012	May 26, 2013
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation adjustments	$ (86.6)	$ 65.4
Other fair value changes:
Securities	0.2	0.2
Hedge derivatives	12.1	(7.5)
Reclassification to earnings:
Hedge derivatives	(2.0)	3.8
Amortization of losses and prior service costs	26.4	24.7
Other comprehensive income (loss), net of tax	(49.9)	86.6
Net earnings attributable to General Mills	459.3	548.9
Net earnings attributable to noncontrolling interests	2.1	2.5
Net earnings attributable to redeemable interests	6.7	10.7
Total comprehensive income (loss) attributable to General Mills	374.2	630.1
Total comprehensive income (loss) attributable to noncontrolling interests	14.1	2.0
Total comprehensive income attributable to redeemable interests	29.9	16.6
Total Equity
Other Comprehensive Income (Loss) Before Tax [Abstract]
Foreign currency translation adjustments	(121.7)	60.3
Other fair value changes:
Securities	0.3	0.3
Hedge derivatives	17.8	(8.6)
Reclassification to earnings:
Hedge derivatives	(1.8)	4.5
Amortization of losses and prior service costs	42.6	40.0
Other comprehensive income (loss), before tax	(62.8)	96.5
Other Comprehensive Income (Loss) Tax [Abstract]
Foreign currency translation adjustments	0	0
Other fair value changes:
Securities	(0.1)	(0.1)
Hedge derivatives	(6.0)	1.5
Reclassification to earnings:
Hedge derivatives	0	(1.4)
Amortization of losses and prior service costs	(16.2)	(15.3)
Other Comprehensive Income (Loss), Tax	(22.3)	(15.3)
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation adjustments	(121.7)	60.3
Other fair value changes:
Securities	0.2	0.2
Hedge derivatives	11.8	(7.1)
Reclassification to earnings:
Hedge derivatives	(1.8)	3.1
Amortization of losses and prior service costs	26.4	24.7
Other comprehensive income (loss), net of tax	(85.1)	81.2
Noncontrolling Interests
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation adjustments	12.0	(0.5)
Other fair value changes:
Securities	0	0
Hedge derivatives	0	0
Reclassification to earnings:
Hedge derivatives	0	0
Amortization of losses and prior service costs	0	0
Other comprehensive income (loss), net of tax	12.0	(0.5)
Redeemable Interests [Member]
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation adjustments	23.1	5.6
Other fair value changes:
Securities	0	0
Hedge derivatives	0.3	(0.4)
Reclassification to earnings:
Hedge derivatives	(0.2)	0.7
Amortization of losses and prior service costs	0	0
Other comprehensive income (loss), net of tax	23.2	5.9
Total comprehensive income attributable to redeemable interests	$ 29.9		$ 42.8