Consolidated Statements of Total Equity and Redeemable Interest (Unaudited) - USD ($) shares in Millions	Total	Redeemable Interest [Member]	Parent [Member]	Issued Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect Period Of Adoption [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Beginning balance, treasury stock shares at May. 31, 2020								(144.8)
Stockholders' Equity, Number of Shares
Shares purchased, shares								0.0
Stock compensation plans, shares								1.6
Ending balance, common stock shares at Nov. 29, 2020				754.6
Ending balance, treasury stock shares at Nov. 29, 2020								(143.2)
Beginning balance, equity at May. 31, 2020	$ 8,349,500,000				$ 1,348,600,000	$ 15,982,100,000	$ (5,700,000)	$ (6,433,300,000)	$ (2,914,400,000)	$ 291,000,000.0
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(100,000)
Stock compensation plans, value					21,200,000			68,000,000.0
Unearned compensation related to stock unit awards					(77,700,000)
Earned compensation					48,200,000
Decrease (increase) in redemption value		$ 7,000,000.0			(7,000,000.0)
Net earnings attributable to General Mills	1,327,300,000		$ 1,327,300,000			1,327,300,000
Comprehensive (loss) income									46,800,000	28,100,000
Cash dividends declared						(929,500,000)
Distributions to noncontrolling interest holders										(16,500,000)
Ending balance, equity at Nov. 29, 2020	8,852,600,000			$ 75,500,000	1,333,300,000	16,374,200,000		$ (6,365,400,000)	(2,867,600,000)	302,600,000
Beginning balance, equity attributable to redeemable noncontrolling interest at May. 31, 2020		544,600,000
Redeemable Interest
Distributions to redeemable interest holder		(22,300,000)
Comprehensive (loss) income		58,400,000
Ending balance, equity attributable to redeemable noncontrolling interest at Nov. 29, 2020		587,700,000
Beginning balance, treasury stock shares at Aug. 30, 2020								(143.3)
Stockholders' Equity, Number of Shares
Shares purchased, shares								0.0
Stock compensation plans, shares								0.1
Ending balance, common stock shares at Nov. 29, 2020				754.6
Ending balance, treasury stock shares at Nov. 29, 2020								(143.2)
Beginning balance, equity at Aug. 30, 2020	8,757,900,000				1,335,500,000	16,312,500,000		$ (6,370,200,000)	(2,908,700,000)	313,300,000
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(100,000)
Stock compensation plans, value					(2,400,000)			4,900,000
Unearned compensation related to stock unit awards					(2,800,000)
Earned compensation					20,000,000.0
Decrease (increase) in redemption value		17,000,000.0			(17,000,000.0)
Net earnings attributable to General Mills	688,400,000		688,400,000			688,400,000
Comprehensive (loss) income									41,100,000	4,700,000
Cash dividends declared						(626,700,000)
Distributions to noncontrolling interest holders										(15,400,000)
Ending balance, equity at Nov. 29, 2020	$ 8,852,600,000			$ 75,500,000	1,333,300,000	16,374,200,000		$ (6,365,400,000)	(2,867,600,000)	302,600,000
Beginning balance, equity attributable to redeemable noncontrolling interest at Aug. 30, 2020		584,900,000
Redeemable Interest
Distributions to redeemable interest holder		(22,300,000)
Comprehensive (loss) income		8,100,000
Ending balance, equity attributable to redeemable noncontrolling interest at Nov. 29, 2020		587,700,000
Beginning balance, common stock shares at May. 30, 2021	754.6
Beginning balance, treasury stock shares at May. 30, 2021	(146.9)							(146.9)
Stockholders' Equity, Number of Shares
Shares purchased, shares								(6.2)
Stock compensation plans, shares								1.7
Ending balance, common stock shares at Nov. 28, 2021	754.6			754.6
Ending balance, treasury stock shares at Nov. 28, 2021	(151.4)							(151.4)
Beginning balance, equity at May. 30, 2021	$ 9,773,200,000				1,365,500,000	17,069,800,000	$ 0	$ (6,611,200,000)	(2,429,200,000)	302,800,000
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(375,000,000.0)
Stock compensation plans, value					4,000,000.0			71,000,000.0
Unearned compensation related to stock unit awards					(72,200,000)
Earned compensation					53,700,000
Decrease (increase) in redemption value		(14,100,000)			14,100,000
Net earnings attributable to General Mills	1,224,200,000		1,224,200,000			1,224,200,000
Comprehensive (loss) income									65,100,000	(20,100,000)
Cash dividends declared						(930,800,000)
Distributions to noncontrolling interest holders										(2,500,000)
Ending balance, equity at Nov. 28, 2021	9,804,700,000			$ 75,500,000	1,365,100,000	17,363,200,000		$ (6,915,200,000)	(2,364,100,000)	280,200,000
Beginning balance, equity attributable to redeemable noncontrolling interest at May. 30, 2021	604,900,000	604,900,000
Redeemable Interest
Distributions to redeemable interest holder		(29,200,000)
Ending balance, equity attributable to redeemable noncontrolling interest at Nov. 28, 2021	$ 561,600,000	561,600,000
Beginning balance, treasury stock shares at Aug. 29, 2021								(148.3)
Stockholders' Equity, Number of Shares
Shares purchased, shares								(3.7)
Stock compensation plans, shares								0.6
Ending balance, common stock shares at Nov. 28, 2021	754.6			754.6
Ending balance, treasury stock shares at Nov. 28, 2021	(151.4)							(151.4)
Beginning balance, equity at Aug. 29, 2021	$ 9,985,900,000				1,345,000,000.0	17,384,500,000		$ (6,715,000,000.0)	(2,397,700,000)	293,500,000
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(224,900,000)
Stock compensation plans, value					(5,100,000)			24,700,000
Unearned compensation related to stock unit awards					(3,900,000)
Earned compensation					20,600,000
Decrease (increase) in redemption value		(8,500,000)			8,500,000
Net earnings attributable to General Mills	597,200,000		$ 597,200,000			597,200,000
Comprehensive (loss) income									33,600,000	(11,900,000)
Cash dividends declared						(618,500,000)
Distributions to noncontrolling interest holders										(1,400,000)
Ending balance, equity at Nov. 28, 2021	9,804,700,000			$ 75,500,000	$ 1,365,100,000	$ 17,363,200,000		$ (6,915,200,000)	$ (2,364,100,000)	$ 280,200,000
Beginning balance, equity attributable to redeemable noncontrolling interest at Aug. 29, 2021		584,000,000.0
Redeemable Interest
Distributions to redeemable interest holder		0
Comprehensive (loss) income		(13,900,000)
Ending balance, equity attributable to redeemable noncontrolling interest at Nov. 28, 2021	$ 561,600,000	$ 561,600,000