Stockholders' Equity (Schedule of total comprehensive income (loss)) (Details) - USD ($)	3 Months Ended
	Aug. 28, 2022	Aug. 29, 2021
Reclassification to earnings:
Foreign currency translation	$ (7,400,000)	$ 0
Other Comprehensive Income (Loss), Net of Tax:
Net earnings attributable to General Mills	820,000,000.0	627,000,000.0
Net earnings attributable to redeemable and noncontrolling interests	3,300,000	11,200,000
Foreign currency translation	3,800,000	(23,900,000)
Other fair value changes:
Hedge derivatives	(38,300,000)	1,700,000
Reclassification to earnings:
Hedge derivatives	(1,400,000)	10,600,000
Amortization of losses and prior service costs	14,100,000	8,400,000
Other comprehensive (loss) income, net of tax	(29,200,000)	(3,200,000)
Total comprehensive income (loss) attributable to General Mills	792,100,000	658,500,000
General Mills [Member]
Other comprehensive income (loss) Pretax:
Foreign currency translation	(48,000,000.0)	(11,900,000)
Other fair value changes:
Hedge derivatives	(49,800,000)	2,800,000
Reclassification to earnings:
Foreign currency translation	(7,400,000)	0
Hedge derivatives	(1,900,000)	12,000,000.0
Amortization of losses and prior service costs	18,200,000	10,800,000
Other comprehensive (loss) income (Pretax)	(88,900,000)	13,700,000
Other comprehensive income (loss) Tax:
Foreign currency translation	53,100,000	22,700,000
Other fair value changes:
Hedge derivatives	11,500,000	(1,000,000.0)
Reclassification to earnings:
Foreign currency translation	0	0
Hedge derivatives	500,000	(1,500,000)
Amortization of losses and prior service costs (b)	(4,100,000)	(2,400,000)
Other comprehensive income (loss), tax	61,000,000.0	17,800,000
Other Comprehensive Income (Loss), Net of Tax:
Net earnings attributable to General Mills	820,000,000.0	627,000,000.0
Foreign currency translation	5,100,000	10,800,000
Other fair value changes:
Hedge derivatives	(38,300,000)	1,800,000
Reclassification to earnings:
Foreign currency translation	(7,400,000)	0
Hedge derivatives	(1,400,000)	10,500,000
Amortization of losses and prior service costs	14,100,000	8,400,000
Other comprehensive (loss) income, net of tax	(27,900,000)	31,500,000
Total comprehensive income (loss) attributable to General Mills	792,100,000	658,500,000
Noncontrolling Interests [Member]
Other Comprehensive Income (Loss), Net of Tax:
Net earnings attributable to redeemable and noncontrolling interests	3,300,000	3,000,000.0
Foreign currency translation	(1,300,000)	(11,200,000)
Other fair value changes:
Hedge derivatives	0	0
Reclassification to earnings:
Foreign currency translation	0	0
Hedge derivatives	0	0
Amortization of losses and prior service costs	0	0
Other comprehensive (loss) income, net of tax	(1,300,000)	(11,200,000)
Total comprehensive income (loss) attributable to noncontrolling interests	$ 2,000,000.0	(8,200,000)
Redeemable Interest [Member]
Other Comprehensive Income (Loss), Net of Tax:
Net earnings attributable to redeemable and noncontrolling interests		8,200,000
Foreign currency translation		(23,500,000)
Other fair value changes:
Hedge derivatives		(100,000)
Reclassification to earnings:
Foreign currency translation		0
Hedge derivatives		100,000
Amortization of losses and prior service costs		0
Other comprehensive (loss) income, net of tax		(23,500,000)
Total comprehensive income (loss) attributable to redeemable interests		$ (15,300,000)