Accumulated Other Comprehensive Income (Loss) (Schecule of amounts reclassified from AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of products sold	$ 1,466	$ 1,298	$ 4,331	$ 4,240
Other expenses / (income)	81	20	115	12
Earnings (loss) from discontinued operations	(2)	39	(1,036)	260
Interest expense	55	89	284	271
Taxes on earnings	52	33	153	147
Net earnings attributable to Campbell Soup Company	(168)	(84)	(1,542)	(219)
Accumulated Translation Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other expenses / (income)	0	0	23	0
Earnings (loss) from discontinued operations	0	0	183	0
Earnings before taxes	0	0	206	0
Taxes on earnings	0	0	4	0
Net earnings attributable to Campbell Soup Company	0	0	210	0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Earnings before taxes	1	(1)	2	0
Taxes on earnings	0	0	(1)	0
Net earnings attributable to Campbell Soup Company	1	(1)	1	0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign Exchange Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of products sold	1	(1)	0	(2)
Other expenses / (income)	0	(1)	0	(1)
Earnings (loss) from discontinued operations	0	0	1	1
Interest expense	0	1	1	2
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense	0	1	1	2
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other expenses / (income)	(7)	(8)	(21)	(22)
Taxes on earnings	2	2	5	5
Net earnings attributable to Campbell Soup Company	$ (5)	$ (6)	$ (16)	$ (17)