Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 23, 2014	Nov. 24, 2013	Nov. 23, 2014	Nov. 24, 2013	May 25, 2014
Net earnings attributable to General Mills	$ 346.1	$ 549.9	$ 691.3	$ 1,009.2
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation	(297.3)	62.1	(389.8)	(24.5)
Other fair value changes:
Securities	0.2	0.5	0.3	0.7
Hedge derivatives	5.8	(8.2)	4.6	3.9
Reclassification to earnings:
Hedge derivatives	1.8	(1.5)	5.3	(3.5)
Amortization of losses and prior service costs	29.5	28.3	53.0	54.7
Other comprehensive income (loss), net of tax	(260.0)	81.2	(326.6)	31.3
Total comprehensive income (loss) attributable to General Mills	161.4	613.6	472.0	987.8
General Mills [Member]
Net earnings attributable to General Mills	346.1	549.9	691.3	1,009.2
Other Comprehensive Income (Loss) Before Tax [Abstract]
Foreign currency translation	(221.7)	43.0	(282.1)	(78.7)
Other fair value changes:
Securities	0.4	0.8	0.6	1.1
Hedge derivatives	7.9	(8.8)	7.1	9.0
Reclassification to earnings:
Hedge derivatives	1.4	(0.8)	4.8	(2.6)
Amortization of losses and prior service costs	47.4	44.6	86.3	87.2
Other comprehensive income (loss), before tax	(164.6)	78.8	(183.3)	16.0
Other Comprehensive Income (Loss) Tax [Abstract]
Foreign currency translation	0	0	0	0
Other fair value changes:
Securities	(0.2)	(0.3)	(0.3)	(0.4)
Hedge derivatives	(1.7)	1.8	(1.5)	(4.2)
Reclassification to earnings:
Hedge derivatives	(0.3)	(0.3)	(0.9)	(0.3)
Amortization of losses and prior service costs	(17.9)	(16.3)	(33.3)	(32.5)
Other Comprehensive Income (Loss), Tax	(20.1)	(15.1)	(36.0)	(37.4)
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation	(221.7)	43.0	(282.1)	(78.7)
Other fair value changes:
Securities	0.2	0.5	0.3	0.7
Hedge derivatives	6.2	(7.0)	5.6	4.8
Reclassification to earnings:
Hedge derivatives	1.1	(1.1)	3.9	(2.9)
Amortization of losses and prior service costs	29.5	28.3	53.0	54.7
Other comprehensive income (loss), net of tax	(184.7)	63.7	(219.3)	(21.4)
Total comprehensive income (loss) attributable to General Mills	161.4	613.6	472.0	987.8
Noncontrolling Interests [Member]
Net earnings attributable to noncontrolling interests	4.0	2.0	5.6	4.1
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation	(26.0)	5.3	(37.6)	17.3
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	(26.0)	5.3	(37.6)	17.3
Total comprehensive income (loss) attributable to noncontrolling interests	(22.0)	7.3	(32.0)	21.4
Redeemable Interests [Member]
Net earnings attributable to redeemable interests	5.3	8.9	10.9	15.6
Other Comprehensive Income (Loss) Net [Abstract]
Foreign currency translation	(49.6)	13.8	(70.1)	36.9
Other fair value changes:
Securities	0	0	0	0
Hedge derivatives	(0.4)	(1.2)	(1.0)	(0.9)
Reclassification to earnings:
Hedge derivatives	0.7	(0.4)	1.4	(0.6)
Amortization of losses and prior service costs	0	0	0	0
Other comprehensive income (loss), net of tax	(49.3)	12.2	(69.7)	35.4
Total comprehensive income attributable to redeemable interests	$ (44.0)	$ 21.1	$ (58.8)	$ 51.0	$ 70.0