Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Aug. 26, 2018	Aug. 27, 2017	May 27, 2018
Net earnings attributable to General Mills		$ 392.3	$ 404.7
Net earnings attributable to redeemable and noncontrolling interests		3.6	3.9
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation		(106.2)	61.5
Other fair value changes:
Securities		0.0	0.3
Hedge derivatives		7.1	(8.8)
Reclassification to earnings:
Securities		(2.0)	0.0
Hedge derivatives		0.6	(0.2)
Amortization of losses and prior service costs		21.9	27.8
Other comprehensive income (loss), net of tax		(78.6)	80.6
Total comprehensive income (loss) attributable to General Mills		322.1	417.2
General Mills [Member]
Net earnings attributable to General Mills		392.3	404.7
Other Comprehensive Income (Loss), Pretax:
Foreign currency translation		(96.8)	(5.3)
Other fair value changes:
Securities		0.0	0.4
Hedge derivatives		7.2	(15.7)
Reclassification to earnings:
Securities	[1]	(2.6)	0.0
Hedge derivatives	[2]	0.5	0.8
Amortization of losses and prior service costs	[3]	26.9	43.8
Other comprehensive income (loss), before tax		(64.8)	24.0
Other Comprehensive Income (Loss), Tax:
Foreign currency translation		0.0	0.0
Other fair value changes:
Securities		0.0	(0.1)
Hedge derivatives		(1.0)	5.2
Reclassification to earnings:
Securities	[1]	0.6	0.0
Hedge derivatives	[2]	0.0	(0.6)
Amortization of losses and prior service costs	[3]	(5.0)	(16.0)
Other comprehensive income (loss), tax		(5.4)	(11.5)
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation		(96.8)	(5.3)
Other fair value changes:
Securities		0.0	0.3
Hedge derivatives		6.2	(10.5)
Reclassification to earnings:
Securities	[1]	(2.0)	0.0
Hedge derivatives	[2]	0.5	0.2
Amortization of losses and prior service costs	[3]	21.9	27.8
Other comprehensive income (loss), net of tax		(70.2)	12.5
Total comprehensive income (loss) attributable to General Mills		322.1	417.2
Noncontrolling Interests [Member]
Net earnings attributable to redeemable and noncontrolling interests		3.1	1.5
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation		(1.3)	21.5
Other fair value changes:
Securities		0.0	0.0
Hedge derivatives		0.0	0.0
Reclassification to earnings:
Securities	[1]	0.0	0.0
Hedge derivatives	[2]	0.0	0.0
Amortization of losses and prior service costs	[3]	0.0	0.0
Other comprehensive income (loss), net of tax		(1.3)	21.5
Total comprehensive income (loss) attributable to noncontrolling interests		1.8	23.0
Redeemable Interests [Member]
Net earnings attributable to redeemable and noncontrolling interests		0.5	2.4
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation		(8.1)	45.3
Other fair value changes:
Securities		0.0	0.0
Hedge derivatives		0.9	1.7
Reclassification to earnings:
Securities	[1]	0.0	0.0
Hedge derivatives	[2]	0.1	(0.4)
Amortization of losses and prior service costs	[3]	0.0	0.0
Other comprehensive income (loss), net of tax		(7.1)	46.6
Total comprehensive income (loss) attributable to redeemable interests		$ (6.6)	$ 49.0	$ 43.6

[1] (a) Gain reclassified from AOCI into earnings is reported in interest, net for securities.

[2] (b) Loss (gain) reclassified from AOCI into earnings is reported in interest, net for interest rate swaps and in cost of sales and SG&A expenses for foreign exchange contracts.

[3] (c) Loss reclassified from AOCI into earnings is reported in benefit plan non-service income. Please refer to Note 17.