STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Nov. 25, 2018	Aug. 26, 2018	Nov. 26, 2017	Aug. 27, 2017	Nov. 25, 2018	Nov. 26, 2017	May 27, 2018
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	$ 3,815.0	$ 3,756.6	$ 3,882.6	$ 4,077.8	$ 3,756.6	$ 4,077.8	$ 4,077.8
Stock option and incentive plans	6.0	9.8	16.0	6.1
Spinoff of Lamb Weston			14.5	1.0
Currency translation adjustment, net	(15.7)	(3.0)	(12.6)	32.5
Issuance of treasury shares	2,816.3
Issuance of common stock	555.7
Repurchase of common shares			(280.0)	(300.0)
Unrealized gain on securities	0.0		0.2	0.2	0.0	0.4
Derivative adjustment, net	79.2	(43.4)	0.7
Activities of noncontrolling interests	2.2	0.0	1.0	0.8
Pension and postretirement healthcare benefits	(0.2)	(0.5)	26.7
Dividends declared on common stock; $0.2125 per share	$ (86.8)	$ (83.2)	$ (86.1)	$ (88.3)
Dividends declared on common stock (in dollars per share)	$ 0.2125	$ 0.2125	$ 0.2125	$ 0.2125
Net income attributable to Conagra Brands, Inc.	$ 131.6	$ 178.2	$ 223.5	$ 152.5	309.8	376.0
Balance at ending of period	$ 7,303.3	$ 3,815.0	$ 3,786.5	$ 3,882.6	$ 7,303.3	$ 3,786.5	3,756.6
Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU							0.0
Accounting Standards Update 2014-09
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU							$ 0.5
Common Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period (in shares)	567.9	567.9	567.9	567.9	567.9	567.9	567.9
Balance at beginning of period	$ 2,839.7	$ 2,839.7	$ 2,839.7	$ 2,839.7	$ 2,839.7	$ 2,839.7	$ 2,839.7
Issuance of common stock (shares)	16.3
Issuance of common stock	$ 81.5
Balance at end of period (in shares)	584.2	567.9	567.9	567.9	584.2	567.9	567.9
Balance at ending of period	$ 2,921.2	$ 2,839.7	$ 2,839.7	$ 2,839.7	$ 2,921.2	$ 2,839.7	$ 2,839.7
Additional Paid-in Capital
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	1,165.6	1,180.0	1,159.9	1,171.9	1,180.0	1,171.9	1,171.9
Stock option and incentive plans	2.2	(14.1)	6.9	(12.0)
Issuance of treasury shares	638.2
Issuance of common stock	474.2
Activities of noncontrolling interests	0.6	(0.3)
Balance at ending of period	2,280.8	1,165.6	1,166.8	1,159.9	2,280.8	1,166.8	1,180.0
Retained Earnings
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	4,841.5	4,744.9	4,312.6	4,247.0	4,744.9	4,247.0	4,247.0
Stock option and incentive plans	0.1	0.5	(0.2)	0.4
Spinoff of Lamb Weston			14.5	1.0
Dividends declared on common stock; $0.2125 per share	(86.8)	(83.2)	(86.1)	(88.3)
Net income attributable to Conagra Brands, Inc.		178.2	223.5	152.5
Balance at ending of period	4,886.4	4,841.5	4,464.3	4,312.6	4,886.4	4,464.3	4,744.9
Retained Earnings | Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU							0.6
Unrealized gain on securities					0.6
Retained Earnings | Accounting Standards Update 2014-09
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU							0.5
Accumulated Other Comprehensive Income (Loss)
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(155.7)	(110.5)	(181.2)	(212.9)	(110.5)	(212.9)	(212.9)
Currency translation adjustment, net	(14.8)	(0.7)	(11.6)	31.5
Unrealized gain on securities			0.2	0.2
Derivative adjustment, net	79.2	(43.4)	0.7
Pension and postretirement healthcare benefits	(0.2)	(0.5)	26.7
Balance at ending of period	(91.5)	(155.7)	(165.2)	(181.2)	(91.5)	(165.2)	(110.5)
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU							(0.6)
Unrealized gain on securities							(0.6)
Treasury Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(4,954.6)	(4,977.9)	(4,337.2)	(4,054.9)	(4,977.9)	(4,054.9)	(4,054.9)
Stock option and incentive plans	3.7	23.3	9.3	17.7
Issuance of treasury shares	2,178.1
Repurchase of common shares			(280.0)	(300.0)
Balance at ending of period	(2,772.8)	(4,954.6)	(4,607.9)	(4,337.2)	(2,772.8)	(4,607.9)	(4,977.9)
Noncontrolling Interests
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	78.5	80.4	88.8	87.0	80.4	87.0	87.0
Stock option and incentive plans		0.1
Currency translation adjustment, net	(0.9)	(2.3)	(1.0)	1.0
Activities of noncontrolling interests	1.6	0.3	1.0	0.8
Balance at ending of period	$ 79.2	$ 78.5	$ 88.8	$ 88.8	$ 79.2	$ 88.8	$ 80.4