Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Aug. 28, 2016	Aug. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss), pre-tax amount	$ 408.0	$ (1,539.5)
Net income (loss), tax (expense) benefit	(218.0)	387.1
Net income (loss)	190.0	(1,152.4)
Other comprehensive income (loss):
Unrealized derivative adjustments, pre-tax amount	(8.0)	0.0
Unrealized derivative adjustments, tax (expense) benefit	3.1	0.0
Unrealized derivative adjustments, after-tax amount	(4.9)	0.0
Unrealized gains (losses) on available-for-sale securities, pre-tax amount	0.2	0.0
Unrealized gains (losses) on available-for-sale securities, tax (expense) benefit	(0.1)	0.0
Unrealized gains (losses) on available-for-sale securities, after-tax amount	0.1	0.0
Unrealized currency translation (losses) gains, pre-tax amount	(11.9)	(37.6)
Unrealized currency translation (losses) gains, tax (expense) benefit	0.2	0.0
Unrealized currency translation (losses) gains, after-tax amount	(11.7)	(37.6)
Pension and post-employment benefit obligations:
Unrealized pension and post-employment benefit obligations, pre-tax amount	(2.1)	6.6
Unrealized pension and post-employment benefit obligations, tax (expense) benefit	0.1	(1.6)
Unrealized pension and post-employment benefit obligations, after-tax amount	(2.0)	5.0
Reclassification for pension and post-employment benefit obligations included in net income, pre-tax amount	(0.9)	(1.3)
Reclassification for pension and post-employment benefit obligations included in net income, tax (expense) benefit	0.3	0.5
Reclassification for pension and post-employment benefit obligations included in net income, after-tax amount	(0.6)	(0.8)
Comprehensive income (loss), pre-tax amount	385.3	(1,571.8)
Comprehensive income (loss), tax (expense) benefit	(214.4)	386.0
Comprehensive income (loss), after-tax amount	170.9	(1,185.8)
Comprehensive income (loss) attributable to noncontrolling interests, pre-tax amount	3.8	(1.1)
Comprehensive income (loss) attributable to noncontrolling interested, tax (expense) benefit	(0.1)	(0.3)
Comprehensive income (loss) attributable to noncontrolling interests, after-tax amount	3.7	(1.4)
Comprehensive income (loss) attributable to ConAgra Foods, Inc., pre-tax amount	381.5	(1,570.7)
Comprehensive income (loss) attributable to ConAgra Foods, Inc., tax (expense) benefit	(214.3)	386.3
Comprehensive income (loss) attributable to ConAgra Foods, Inc., after-tax amount	$ 167.2	$ (1,184.4)