Stockholders' Equity (Schedule of total comprehensive income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 30, 2021	Feb. 28, 2021	Nov. 29, 2020	Aug. 30, 2020	May 31, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	May 30, 2021	May 31, 2020	May 26, 2019
Other comprehensive income (loss), net of tax:
Foreign currency translation									$ 175.1	$ (169.1)	$ (82.8)
Net actuarial gain (loss)									353.4	(224.6)	(253.4)
Other fair value changes:
Hedge derivatives									(20.7)	3.2	12.1
Reclassification to earnings:
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax									0.0	0.0	2.0
Hedge derivatives									13.5	4.1	0.9
Amortization of losses and prior service costs									78.9	77.9	84.6
Other comprehensive income (loss), net of tax									600.2	(308.5)	(240.6)
Comprehensive Income:
Net earnings attributable to General Mills	$ 416.8	$ 595.7	$ 688.4	$ 638.9	$ 625.7	$ 454.1	$ 580.8	$ 520.6	2,339.8	2,181.2	1,752.7
Net earnings attributable to redeemable and noncontrolling interests									6.2	29.6	33.5
Total comprehensive income (loss) attributable to General Mills									2,825.0	1,892.2	1,556.3
General Mills [Member]
Other comprehensive income (loss), before tax:
Foreign currency translation									(6.1)	(149.1)	(38.3)
Net actuarial gain (loss)									464.9	(290.2)	(325.6)
Other fair value chages:
Hedge derivaties									(25.8)	4.4	15.9
Reclassification to earnings:
Securities											(2.6)
Hedge derivatives									19.1	4.3	0.1
Amortization of losses and prior service costs									102.5	101.3	107.5
Other comprehensive income (loss), before tax									554.6	(329.3)	(243.0)
Other comprehensive income (loss), tax:
Foreign currency translation									64.9	0.0	0.0
Net actuarial gain (loss)									(111.5)	65.6	72.2
Other fair value changes:
Hedge derivatives									6.5	(1.2)	(3.7)
Reclassification to earnings:
Securities											0.6
Hedge derivatives									(5.7)	(0.7)	0.4
Amortization of losses and prior service costs									(23.6)	(23.4)	(22.9)
Other comprehensive income (loss), tax									(69.4)	40.3	46.6
Other comprehensive income (loss), net of tax:
Foreign currency translation									58.8	(149.1)	(38.3)
Net actuarial gain (loss)									353.4	(224.6)	(253.4)
Other fair value changes:
Hedge derivatives									(19.3)	3.2	12.2
Reclassification to earnings:
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax											(2.0)
Hedge derivatives									13.4	3.6	0.5
Amortization of losses and prior service costs									78.9	77.9	84.6
Other comprehensive income (loss), net of tax									485.2	(289.0)	(196.4)
Comprehensive Income:
Net earnings attributable to General Mills									2,339.8	2,181.2	1,752.7
Total comprehensive income (loss) attributable to General Mills									2,825.0	1,892.2	1,556.3
Noncontrolling Interests [Member]
Other comprehensive income (loss), net of tax:
Foreign currency translation									31.5	(2.6)	(13.5)
Net actuarial gain (loss)									0.0	0.0	0.0
Other fair value changes:
Hedge derivatives									0.0	0.0	0.0
Reclassification to earnings:
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax											0.0
Hedge derivatives									0.0	0.0	0.0
Amortization of losses and prior service costs									0.0	0.0	0.0
Other comprehensive income (loss), net of tax									31.5	(2.6)	(13.5)
Comprehensive Income:
Net earnings attributable to redeemable and noncontrolling interests									6.5	12.9	13.9
Total comprehensive income (loss) attributable to noncontrolling interests									38.0	10.3	0.4
Redeemable Interest [Member]
Other comprehensive income (loss), net of tax:
Foreign currency translation									84.8	(17.4)	(31.0)
Net actuarial gain (loss)									0.0	0.0	0.0
Other fair value changes:
Hedge derivatives									(1.4)	0.0	(0.1)
Reclassification to earnings:
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax											0.0
Hedge derivatives									0.1	0.5	0.4
Amortization of losses and prior service costs									0.0	0.0	0.0
Other comprehensive income (loss), net of tax									83.5	(16.9)	(30.7)
Comprehensive Income:
Net earnings attributable to redeemable and noncontrolling interests									(0.3)	16.7	19.6
Total comprehensive income (loss) attributable to redeemable interests									$ 83.2	$ (0.2)	$ (11.1)