Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019
Statement of Comprehensive Income [Abstract]
Net earnings	$ 168	$ 84	$ 1,542	$ 219
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Foreign currency translation adjustments, before tax	(13)	(26)	(10)	(49)
Reclassification of currency translation adjustments realized upon disposal of business, before tax			206	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	8	2	9	1
Reclassification adjustment for (gains) losses included in net earnings, before tax	1	(1)	2	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]
Reclassification of prior service credit included in net earnings, before tax	(7)	(8)	(21)	(22)
Other comprehensive income (loss), before tax	(11)	(33)	186	(70)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Foreign currency translation adjustments, tax (expense) benefit	0	0	0	0
Reclassification of currency translation adjustments realized upon disposal of business, tax (expense) benefit			4	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(2)	0	(2)	0
Reclassification adjustment for (gains) losses included in net earnings, tax (expense) benefit	0	0	(1)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax [Abstract]
Reclassification of prior service credit included in net earnings, tax (expense) benefit	2	2	5	5
Other comprehensive income (loss), tax (expense) benefit	0	2	6	5
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Foreign currency translation adjustments, after-tax	(13)	(26)	(10)	(49)
Reclassification of currency translation adjustments realized upon disposal of business, after-tax			(210)	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Unrealized gains (losses) arising during the period, after-tax	6	2	7	1
Reclassification adjustment for (gains) losses included in net earnings, after-tax	1	(1)	1	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Reclassification of prior service credit included in net earnings, after-tax	(5)	(6)	(16)	(17)
Other comprehensive income (loss), after tax	(11)	(31)	192	(65)
Total comprehensive income (loss), after-tax	157	53	1,734	154
Total comprehensive income (loss) attributable to noncontrolling interests	1	0	1	0
Total comprehensive income (loss) attributable to Campbell Soup Company	$ 156	$ 53	$ 1,733	$ 154