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BUSINESS SEGMENTS AND RELATED INFORMATION - Schedule of Segment Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 28, 2017	Feb. 26, 2017	Nov. 27, 2016	Aug. 28, 2016	May 29, 2016	Feb. 28, 2016	Nov. 29, 2015	Aug. 30, 2015	May 28, 2017	May 29, 2016	May 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 1,861.7	$ 1,981.2	$ 2,088.4	$ 1,895.6	$ 2,053.0	$ 2,199.3	$ 2,358.8	$ 2,053.0	$ 7,826.9	$ 8,664.1	$ 9,034.0
Operating profit									1,238.3	1,223.1	1,209.4
Equity method investment earnings									71.2	66.1	79.4
General corporate expenses									313.3	818.5	296.6
Interest expense, net									195.5	295.8	328.2
Income tax expense									254.7	46.4	212.7
Income from continuing operations	$ 153.6	$ 179.5	$ 114.3	$ 98.6	$ (116.6)	$ 71.4	$ 80.1	$ 93.6	546.0	128.5	451.3
Less: Net income attributable to noncontrolling interests of continuing operations									1.9	1.9	2.5
Income from continuing operations attributable to Conagra Brands, Inc.									544.1	126.6	448.8
Grocery & Snacks
Segment Reporting Information [Line Items]
Net sales									3,208.8	3,377.1	3,509.9
Operating profit									653.7	592.9	589.9
Refrigerated & Frozen
Segment Reporting Information [Line Items]
Net sales									2,652.7	2,867.8	2,986.6
Operating profit									445.8	420.4	376.3
International
Segment Reporting Information [Line Items]
Net sales									816.0	846.6	942.7
Operating profit									(168.9)	66.7	90.3
Foodservice
Segment Reporting Information [Line Items]
Net sales									1,078.3	1,104.5	1,120.1
Operating profit									105.1	97.7	109.4
Commercial
Segment Reporting Information [Line Items]
Net sales									71.1	468.1	474.7
Operating profit									$ 202.6	$ 45.4	$ 43.5