Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 22, 2015	Feb. 23, 2014	Feb. 22, 2015	Feb. 23, 2014	May 25, 2014
Net earnings attributable to General Mills	$ 343.2	$ 410.6	$ 1,034.5	$ 1,419.8
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(411.3)	(59.2)	(801.1)	(83.7)
Other fair value changes:
Securities	0.5	(0.4)	0.8	0.3
Hedge derivatives	10.9	8.2	15.5	12.1
Reclassification to earnings:
Hedge derivatives	(0.1)	0	5.2	(3.5)
Amortization of losses and prior service costs	27.8	26.6	80.8	81.3
Other comprehensive income (loss), net of tax	(372.2)	(24.8)	(698.8)	6.5
Total comprehensive income (loss) attributable to General Mills	65.0	376.7	537.0	1,364.5
General Mills [Member]
Net earnings attributable to General Mills	343.2	410.6	1,034.5	1,419.8
Other Comprehensive Income (Loss), Pretax:
Foreign currency translation	(319.3)	(68.6)	(601.4)	(147.3)
Other fair value changes:
Securities	0.6	(0.6)	1.2	0.5
Hedge derivatives	20.3	12.3	27.4	21.3
Reclassification to earnings:
Hedge derivatives	(0.8)	(0.2)	4.0	(2.8)
Amortization of losses and prior service costs	44.8	43.0	131.1	130.2
Other comprehensive income (loss), before tax	(254.4)	(14.1)	(437.7)	1.9
Other Comprehensive Income (Loss), Tax:
Foreign currency translation	0	0	0	0
Other fair value changes:
Securities	(0.1)	0.2	(0.4)	(0.2)
Hedge derivatives	(6.8)	(3.6)	(8.3)	(7.8)
Reclassification to earnings:
Hedge derivatives	0.1	0	(0.8)	(0.3)
Amortization of losses and prior service costs	(17.0)	(16.4)	(50.3)	(48.9)
Other Comprehensive Income (Loss), Tax	(23.8)	(19.8)	(59.8)	(57.2)
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(319.3)	(68.6)	(601.4)	(147.3)
Other fair value changes:
Securities	0.5	(0.4)	0.8	0.3
Hedge derivatives	13.5	8.7	19.1	13.5
Reclassification to earnings:
Hedge derivatives	(0.7)	(0.2)	3.2	(3.1)
Amortization of losses and prior service costs	27.8	26.6	80.8	81.3
Other comprehensive income (loss), net of tax	(278.2)	(33.9)	(497.5)	(55.3)
Total comprehensive income (loss) attributable to General Mills	65.0	376.7	537.0	1,364.5
Noncontrolling Interests [Member]
Net earnings attributable to noncontrolling interests	2.1	(2.3)	7.7	1.8
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(29.2)	4.7	(66.8)	22.0
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	(29.2)	4.7	(66.8)	22.0
Total comprehensive income (loss) attributable to noncontrolling interests	(27.1)	2.4	(59.1)	23.8
Redeemable Interests [Member]
Net earnings attributable to redeemable interests	8.5	8.7	19.4	24.3
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	(62.8)	4.7	(132.9)	41.6
Other fair value changes:
Securities	0	0	0	0
Hedge derivatives	(2.6)	(0.5)	(3.6)	(1.4)
Reclassification to earnings:
Hedge derivatives	0.6	0.2	2.0	(0.4)
Amortization of losses and prior service costs	0	0	0	0
Other comprehensive income (loss), net of tax	(64.8)	4.4	(134.5)	39.8
Total comprehensive income (loss) attributable to redeemable interests	$ (56.3)	$ 13.1	$ (115.1)	$ 64.1	$ 70.0