Earnings Per Share - Schedule of Reconciliation of Income and Average Share Amounts to Compute Basic and Diluted Earnings Per Share (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 25, 2012	Nov. 27, 2011	Nov. 25, 2012	Nov. 27, 2011
Net income available to ConAgra Foods, Inc. common stockholders:
Income from continuing operations attributable to ConAgra Foods, Inc. common stockholders	$ 211.6	$ 180.2	$ 461.7	$ 273.9
Income from discontinued operations, net of tax, attributable to ConAgra Foods, Inc. common stockholders				0.1
Net income attributable to ConAgra Foods, Inc.	211.6	180.2	461.7	274.0
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	0.4	0.7	0.8	1.0
Net income available to ConAgra Foods, Inc. common stockholders	$ 211.2	$ 179.5	$ 460.9	$ 273.0
Weighted average shares outstanding:
Basic weighted average shares outstanding	405.9	413.6	406.5	413.0
Add: Dilutive effect of stock options, restricted stock awards, and other dilutive securities	5.8	5.0	5.3	5.4
Diluted weighted average shares outstanding	411.7	418.6	411.8	418.4