Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 26, 2020	Jan. 31, 2021	Jan. 26, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 245	$ 1,208	$ 554	$ 1,374
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Foreign currency translation adjustments, before tax	7	7	7	3
Reclassification of currency translation adjustments realized upon disposal of business, before tax	0	124	0	206
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax [Abstract]
Unrealized gains (losses) arising during the period, before tax	(6)	1	(7)	1
Reclassification adjustment for (gains) losses included in net earnings, before tax	3	(1)	3	1
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	(1)	(7)	(2)	(14)
Other comprehensive income (loss), before tax	3	124	1	197
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	0	4	0	4
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax [Abstract]
Unrealized gains (losses) arising during the period, tax (expense) benefit	0	0	1	0
Reclassification adjustment for (gains) losses included in net earnings, tax (expense) benefit	0	0	0	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax [Abstract]
Reclassification of prior service credit included in net earnings, tax (expense) benefit	0	2	0	3
Other comprehensive income (loss), tax (expense) benefit	0	6	1	6
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Foreign currency translation adjustments, after-tax	7	7	7	3
Reclassification of currency transaction adjustments realized upon disposal of business, after-tax	0	128	0	210
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Unrealized gains (losses) arising during the period, after-tax	(6)	1	(6)	1
Reclassification adjustment for (gains) losses included in net earnings, after-tax	3	(1)	3	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	(1)	(5)	(2)	(11)
Other comprehensive income (loss), after tax	3	130	2	203
Total comprehensive income (loss), after-tax	248	1,338	556	1,577
Total comprehensive income (loss) attributable to noncontrolling interests	(1)	(1)	(3)	0
Total comprehensive income (loss) attributable to Campbell Soup Company	$ 249	$ 1,339	$ 559	$ 1,577