Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) - USD ($) $ in Millions	3 Months Ended								9 Months Ended
	Feb. 24, 2019		Nov. 25, 2018	Aug. 26, 2018	Feb. 25, 2018		Nov. 26, 2017	Aug. 27, 2017	Feb. 24, 2019		Feb. 25, 2018
Net earnings attributable to General Mills	$ 446.8				$ 941.4				$ 1,182.5		$ 1,776.6
Net earnings attributable to redeemable and noncontrolling interests	11.1				11.1				22.5		28.3
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	48.7				23.5				(20.1)		43.0
Other fair value changes:
Securities	0.0				0.6				0.0		1.4
Hedge derivatives	(7.7)				(6.7)				1.5		(15.6)
Reclassification to earnings:
Securities	0.0				0.0				(2.0)		0.0
Hedge derivatives	(1.2)				2.8				(0.5)		3.4
Amortization of losses and prior service costs	21.0				30.7				63.5		86.4
Other comprehensive income (loss), net of tax	60.8				50.9				42.4		118.6
Total comprehensive income (loss) attributable to General Mills	505.7				962.7				1,251.2		1,798.0
General Mills [Member]
Net earnings attributable to General Mills	446.8				941.4				1,182.5		1,776.6
Other Comprehensive Income (Loss), Pretax:
Foreign currency translation	46.1				(6.9)				5.8		(55.5)
Other fair value changes:
Securities	0.0				0.8				0.0		2.1
Hedge derivatives	(5.9)				(7.2)				3.3		(19.4)
Reclassification to earnings:
Securities	0.0				0.0				(2.6)	[1]	0.0	[1]
Hedge derivatives	(2.0)	[2]			3.9	[2]			(1.0)	[3]	7.2	[3]
Amortization of losses and prior service costs	27.3	[4]			45.1	[4]			81.0	[5]	132.7	[5]
Other comprehensive income (loss), before tax	65.5				35.7				86.5		67.1
Other Comprehensive Income (Loss), Tax:
Foreign currency translation	0.0				0.0				0.0		0.0
Other fair value changes:
Securities	0.0				(0.2)				0.0		(0.7)
Hedge derivatives	(1.0)				1.2				(1.3)		3.9
Reclassification to earnings:
Securities	0.0				0.0				0.6	[1]	0.0	[1]
Hedge derivatives	0.7	[2]			(1.0)	[2]			0.4	[3]	(2.6)	[3]
Amortization of losses and prior service costs	(6.3)	[4]			(14.4)	[4]			(17.5)	[5]	(46.3)	[5]
Other comprehensive income (loss), tax	(6.6)				(14.4)				(17.8)		(45.7)
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	46.1				(6.9)				5.8		(55.5)
Other fair value changes:
Securities	0.0				0.6				0.0		1.4
Hedge derivatives	(6.9)				(6.0)				2.0		(15.5)
Reclassification to earnings:
Securities	0.0				0.0				(2.0)	[1]	0.0	[1]
Hedge derivatives	(1.3)	[2]			2.9	[2]			(0.6)	[3]	4.6	[3]
Amortization of losses and prior service costs	21.0	[4]			30.7	[4]			63.5	[5]	86.4	[5]
Other comprehensive income (loss), net of tax	58.9				21.3				68.7		21.4
Total comprehensive income (loss) attributable to General Mills	505.7				962.7				1,251.2		1,798.0
Noncontrolling Interests [Member]
Net earnings attributable to redeemable and noncontrolling interests	2.5				2.8				10.7		8.8
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	0.1				10.3				(9.5)		32.4
Other fair value changes:
Securities	0.0				0.0				0.0		0.0
Hedge derivatives	0.0				0.0				0.0		0.0
Reclassification to earnings:
Securities	0.0				0.0				0.0	[1]	0.0	[1]
Hedge derivatives	0.0	[2]			0.0	[2]			0.0	[3]	0.0	[3]
Amortization of losses and prior service costs	0.0	[4]			0.0	[4]			0.0	[5]	0.0	[5]
Other comprehensive income (loss), net of tax	0.1				10.3				(9.5)		32.4
Total comprehensive income (loss) attributable to noncontrolling interests	2.6				13.1				1.2		41.2
Redeemable Interests [Member]
Net earnings attributable to redeemable and noncontrolling interests	8.6				8.3				11.8		19.5
Other Comprehensive Income (Loss), Net of Tax:
Foreign currency translation	2.5				20.1				(16.4)		66.1
Other fair value changes:
Securities	0.0				0.0				0.0		0.0
Hedge derivatives	(0.8)				(0.7)				(0.5)		(0.1)
Reclassification to earnings:
Securities	0.0				0.0				0.0	[1]	0.0	[1]
Hedge derivatives	0.1	[2]			(0.1)	[2]			0.1	[3]	(1.2)	[3]
Amortization of losses and prior service costs	0.0	[4]			0.0	[4]			0.0	[5]	0.0	[5]
Other comprehensive income (loss), net of tax	1.8				19.3				(16.8)		64.8
Total comprehensive income (loss) attributable to redeemable interests	$ 10.4		$ (8.8)	$ (6.6)	$ 27.6		$ 7.7	$ 49.0	$ (5.0)		$ 84.3

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

[2] 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] 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.

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

[5] Loss reclassified from AOCI into earnings is reported in benefit plan non-service income. Please refer t o Note 17.