STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended		12 Months Ended
	Feb. 24, 2019	Nov. 25, 2018	Aug. 26, 2018	Feb. 25, 2018	Nov. 26, 2017	Aug. 27, 2017	Feb. 24, 2019	Feb. 25, 2018	May 27, 2018	May 28, 2018	Nov. 27, 2017
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	$ 7,303.3	$ 3,815.0	$ 3,756.6	$ 3,786.5	$ 3,882.6	$ 4,077.8	$ 3,756.6	$ 4,077.8	$ 4,077.8
Stock option and incentive plans	4.0	6.0	9.8	18.1	16.0	6.1
Spinoff of Lamb Weston				(0.7)	14.5	1.0
Currency translation adjustment, net	7.4	(15.7)	(3.0)	5.0	(12.6)	32.5
Issuance of treasury shares		2,816.3
Issuance of common stock		555.7
Repurchase of common shares				(280.0)	(280.0)	(300.0)
Unrealized gain on securities	0.0			0.6	0.2	0.2	0.0	1.0
Derivative adjustment, net	(2.0)	79.2	(43.4)	0.9	0.7
Activities of noncontrolling interests	0.1	2.2	0.0	0.9	1.0	0.8
Pension and postretirement healthcare benefits	(0.1)	(0.2)	(0.5)	(0.1)	26.7
Dividends declared on common stock; $0.2125 per share	$ (103.2)	$ (86.8)	$ (83.2)	$ (84.5)	$ (86.1)	$ (88.3)
Dividends declared on common stock (in dollars per share)	$ 0.2125	$ 0.2125	$ 0.2125	$ 0.2125	$ 0.2125	$ 0.2125
Net income attributable to Conagra Brands, Inc.	$ 242.0	$ 131.6	$ 178.2	$ 362.8	$ 223.5	$ 152.5	551.8	738.8
Balance at ending of period	$ 7,451.5	$ 7,303.3	$ 3,815.0	$ 3,809.5	$ 3,786.5	$ 3,882.6	$ 7,451.5	$ 3,809.5	$ 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
Accounting Standards Update 2018-02
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU											$ 0.0
Common Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period (in shares)	584.2	567.9	567.9	567.9	567.9	567.9	567.9	567.9	567.9
Balance at beginning of period	$ 2,921.2	$ 2,839.7	$ 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	584.2	567.9	567.9	567.9	567.9	584.2	567.9	567.9
Balance at ending of period	$ 2,921.2	$ 2,921.2	$ 2,839.7	$ 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	2,280.8	1,165.6	1,180.0	1,166.8	1,159.9	1,171.9	1,180.0	1,171.9	1,171.9
Stock option and incentive plans	(3.9)	2.2	(14.1)	6.9	6.9	(12.0)
Issuance of treasury shares		638.2
Issuance of common stock		474.2
Activities of noncontrolling interests	0.3	0.6	(0.3)
Balance at ending of period	2,277.2	2,280.8	1,165.6	1,173.7	1,166.8	1,159.9	2,277.2	1,173.7	1,180.0
Retained Earnings
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	4,886.4	4,841.5	4,744.9	4,464.3	4,312.6	4,247.0	4,744.9	4,247.0	4,247.0
Stock option and incentive plans	0.1	0.1	0.5	(0.5)	(0.2)	0.4
Spinoff of Lamb Weston				(0.7)	14.5	1.0
Dividends declared on common stock; $0.2125 per share	(103.2)	(86.8)	(83.2)	(84.5)	(86.1)	(88.3)
Net income attributable to Conagra Brands, Inc.		131.6	178.2		223.5	152.5
Balance at ending of period	5,025.3	4,886.4	4,841.5	4,758.8	4,464.3	4,312.6	5,025.3	4,758.8	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
Retained Earnings | Accounting Standards Update 2018-02
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU											17.4
Accumulated Other Comprehensive Income (Loss)
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(91.5)	(155.7)	(110.5)	(165.2)	(181.2)	(212.9)	(110.5)	(212.9)	(212.9)
Currency translation adjustment, net	7.9	(14.8)	(0.7)	5.7	(11.6)	31.5
Unrealized gain on securities				0.6	0.2	0.2
Derivative adjustment, net	(2.0)	79.2	(43.4)	0.9	0.7
Pension and postretirement healthcare benefits	(0.1)	(0.2)	(0.5)	(0.1)	26.7
Balance at ending of period	(85.7)	(91.5)	(155.7)	(175.5)	(165.2)	(181.2)	(85.7)	(175.5)	(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)
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2018-02
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU											$ (17.4)
Treasury Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(2,772.8)	(4,954.6)	(4,977.9)	(4,607.9)	(4,337.2)	(4,054.9)	(4,977.9)	(4,054.9)	(4,054.9)
Stock option and incentive plans	7.8	3.7	23.3	11.7	9.3	17.7
Issuance of treasury shares		2,178.1
Repurchase of common shares				(280.0)	(280.0)	(300.0)
Balance at ending of period	(2,765.0)	(2,772.8)	(4,954.6)	(4,876.2)	(4,607.9)	(4,337.2)	(2,765.0)	(4,876.2)	(4,977.9)
Noncontrolling Interests
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	79.2	78.5	80.4	88.8	88.8	87.0	80.4	87.0	87.0
Stock option and incentive plans			0.1
Currency translation adjustment, net	(0.5)	(0.9)	(2.3)	(0.7)	(1.0)	1.0
Activities of noncontrolling interests	(0.2)	1.6	0.3	0.9	1.0	0.8
Balance at ending of period	$ 78.5	$ 79.2	$ 78.5	$ 89.0	$ 88.8	$ 88.8	$ 78.5	$ 89.0	$ 80.4