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								2.0
Ending balance, common stock shares at Feb. 28, 2021				754.6
Ending balance, treasury stock shares at Feb. 28, 2021								(142.8)
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								(600,000)
Stock compensation plans, value					12,900,000			82,600,000
Unearned compensation related to stock unit awards					(78,200,000)
Earned compensation					68,900,000
Decrease in redemption value of redeemable interest		$ (1,600,000)			1,600,000
Net earnings attributable to General Mills	1,923,000,000.0		$ 1,923,000,000.0			1,923,000,000.0
Comprehensive (loss) income									71,700,000	31,800,000
Cash dividends declared						(1,244,400,000)
Distributions to noncontrolling interest holders										(25,200,000)
Reclassification of Redeemable Interest										0
Reversal of Cumulative Redeemable Interest Value Adjustments					0					0
Acquisition of noncontrolling interest					(19,500,000)
Divestiture										0
Ending balance, equity at Feb. 28, 2021	9,187,900,000			$ 75,500,000	1,353,800,000	16,655,000,000.0		$ (6,351,300,000)	(2,842,700,000)	297,600,000
Beginning balance, equity attributable to redeemable noncontrolling interest at May. 31, 2020		544,600,000
Redeemable Interest
Distributions to redeemable interest holder		(22,700,000)
Reclassification to noncontrolling interest		0
Comprehensive (loss) income		75,700,000
Ending balance, equity attributable to redeemable noncontrolling interest at Feb. 28, 2021		596,000,000.0
Beginning balance, treasury stock shares at Nov. 29, 2020								(143.2)
Stockholders' Equity, Number of Shares
Shares purchased, shares								0.0
Stock compensation plans, shares								0.4
Ending balance, common stock shares at Feb. 28, 2021				754.6
Ending balance, treasury stock shares at Feb. 28, 2021								(142.8)
Beginning balance, equity at Nov. 29, 2020	8,852,600,000				1,333,300,000	16,374,200,000		$ (6,365,400,000)	(2,867,600,000)	302,600,000
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(500,000)
Stock compensation plans, value					(8,300,000)			14,600,000
Unearned compensation related to stock unit awards					(500,000)
Earned compensation					20,700,000
Decrease in redemption value of redeemable interest		(8,600,000)			8,600,000
Net earnings attributable to General Mills	595,700,000		595,700,000			595,700,000
Comprehensive (loss) income									24,900,000	3,700,000
Cash dividends declared						(314,900,000)
Distributions to noncontrolling interest holders										(8,700,000)
Reclassification of Redeemable Interest										0
Reversal of Cumulative Redeemable Interest Value Adjustments					0					0
Acquisition of noncontrolling interest					0
Divestiture										0
Ending balance, equity at Feb. 28, 2021	$ 9,187,900,000			$ 75,500,000	1,353,800,000	16,655,000,000.0		$ (6,351,300,000)	(2,842,700,000)	297,600,000
Beginning balance, equity attributable to redeemable noncontrolling interest at Nov. 29, 2020		587,700,000
Redeemable Interest
Distributions to redeemable interest holder		(400,000)
Reclassification to noncontrolling interest		0
Comprehensive (loss) income		17,300,000
Ending balance, equity attributable to redeemable noncontrolling interest at Feb. 28, 2021		596,000,000.0
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								(8.8)
Stock compensation plans, shares								3.3
Ending balance, common stock shares at Feb. 27, 2022	754.6			754.6
Ending balance, treasury stock shares at Feb. 27, 2022	(152.4)							(152.4)
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								(550,500,000)
Stock compensation plans, value					15,500,000			146,400,000
Unearned compensation related to stock unit awards					(91,300,000)
Earned compensation					85,400,000
Decrease in redemption value of redeemable interest		(14,100,000)			14,100,000
Net earnings attributable to General Mills	1,884,500,000		1,884,500,000			1,884,500,000
Comprehensive (loss) income									306,500,000	(17,800,000)
Cash dividends declared						(1,241,200,000)
Distributions to noncontrolling interest holders										(110,800,000)
Reclassification of Redeemable Interest										561,600,000
Reversal of Cumulative Redeemable Interest Value Adjustments					(207,400,000)					207,400,000
Acquisition of noncontrolling interest					0
Divestiture										(680,400,000)
Ending balance, equity at Feb. 27, 2022	10,075,700,000			$ 75,500,000	1,162,300,000	17,713,100,000		$ (7,015,300,000)	(2,122,700,000)	262,800,000
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)
Reclassification to noncontrolling interest		(561,600,000)
Ending balance, equity attributable to redeemable noncontrolling interest at Feb. 27, 2022	$ 0	0
Beginning balance, treasury stock shares at Nov. 28, 2021								(151.4)
Stockholders' Equity, Number of Shares
Shares purchased, shares								(2.6)
Stock compensation plans, shares								1.6
Ending balance, common stock shares at Feb. 27, 2022	754.6			754.6
Ending balance, treasury stock shares at Feb. 27, 2022	(152.4)							(152.4)
Beginning balance, equity at Nov. 28, 2021	$ 9,804,700,000				1,365,100,000	17,363,200,000		$ (6,915,200,000)	(2,364,100,000)	280,200,000
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Shares purchased, value								(175,500,000)
Stock compensation plans, value					11,500,000			75,400,000
Unearned compensation related to stock unit awards					(19,100,000)
Earned compensation					31,700,000
Decrease in redemption value of redeemable interest		0			0
Net earnings attributable to General Mills	660,300,000		$ 660,300,000			660,300,000
Comprehensive (loss) income									241,400,000	2,300,000
Cash dividends declared						(310,400,000)
Distributions to noncontrolling interest holders										(108,300,000)
Reclassification of Redeemable Interest										561,600,000
Reversal of Cumulative Redeemable Interest Value Adjustments					(207,400,000)					207,400,000
Acquisition of noncontrolling interest					(19,500,000)
Divestiture										(680,400,000)
Ending balance, equity at Feb. 27, 2022	10,075,700,000			$ 75,500,000	$ 1,162,300,000	$ 17,713,100,000		$ (7,015,300,000)	$ (2,122,700,000)	$ 262,800,000
Beginning balance, equity attributable to redeemable noncontrolling interest at Nov. 28, 2021		561,600,000
Redeemable Interest
Distributions to redeemable interest holder		0
Reclassification to noncontrolling interest		(561,600,000)
Comprehensive (loss) income		0
Ending balance, equity attributable to redeemable noncontrolling interest at Feb. 27, 2022	$ 0	$ 0