Quarterly Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Aug. 02, 2020		Apr. 26, 2020		Jan. 26, 2020		Oct. 27, 2019		Jul. 28, 2019		Apr. 28, 2019		Jan. 27, 2019		Oct. 28, 2018		Aug. 02, 2020		Jul. 28, 2019		Jul. 29, 2018
Net sales	$ 2,108		$ 2,238		$ 2,162		$ 2,183		$ 1,780		$ 1,953		$ 2,172		$ 2,202		$ 8,691		$ 8,107		$ 6,615
Gross profit	747		772		742		738		606		655		706		726
Earnings (loss) from continuing operations	86		166		171		169		(5)		123		176		180
Earnings (loss) from discontinued operations	0		2		1,037		(3)		(3)		(39)		(235)		14		1,036		(263)		(463)
Net earnings (loss) attributable to Campbell Soup Company	$ 86		$ 168		$ 1,208		$ 166		$ (8)		$ 84		$ (59)		$ 194		$ 1,628		$ 211		$ 261
Earnings (loss) from continuing operations attributable to Campbell Soup Company per share, basic	$ 0.28		$ 0.55		$ 0.57		$ 0.56		$ (0.02)		$ 0.41		$ 0.58		$ 0.60		$ 1.96		$ 1.57		$ 2.41
Earnings (loss) from discontinued operations per share, basic	0		0.01		3.43		(0.01)		(0.01)		(0.13)		(0.78)		0.05		3.43		(0.87)		(1.54)
Earnings (loss) per share, basic	0.28	[1]	0.56	[1]	4.00	[1]	0.55	[1]	(0.03)	[1]	0.28	[1]	(0.20)	[1]	0.64	[1]	5.39		0.70		0.87
Common Stock, Dividends, Per Share, Declared	0.35		0.35		0.35		0.35		0.35		0.35		0.35		0.35		1.40		1.40		1.40
Earnings (loss) from continuing operations attributable to Campbell Soup Company Per Share, Diluted	0.28		0.55		0.56		0.56		(0.02)		0.41		0.58		0.60		1.95		1.57		2.40
Earnings (loss) from discontinued operations Per Share, Diluted	0		0.01		3.41		(0.01)		(0.01)		(0.13)		(0.78)		0.05		3.41		(0.87)		(1.53)
Earnings (loss) Per Share, Diluted	$ 0.28	[1]	$ 0.55	[1]	$ 3.97	[1]	$ 0.55	[1]	$ (0.03)	[1]	$ 0.28	[1]	$ (0.20)	[1]	$ 0.64	[1]	$ 5.36	[2]	$ 0.70	[2]	$ 0.86	[2]
Restructuring charges, implementation costs and other related costs, net of tax	$ 14		$ 11		$ 19		$ 8		$ 24		$ 16		$ 18		$ 34
Charges (gains) Associated with Divestitures, net of tax	0		0		(19)		60
Loss on extinguishment of debt, net of tax	0		0		57		0
Charges (gains) related to pension settlement, net of tax	0		41		(8)		0		0		22		0		0
Investment losses, net of tax	0		35		0		0
Pension and postretirement benefits mark to market adj, net of tax	$ 92		$ 0		$ 0		$ 0		93		0		0		0
Tax Cuts and Jobs Act of 2017, Provisional Income Tax Expense (Benefit)									0		0		2		0
Asset Impairment Charges, net of tax									$ 13		$ 0		$ 0		$ 0
Restructuring charges, Per Diluted Share	$ 0.05		$ 0.04		$ 0.06		$ 0.03		$ 0.08		$ 0.05		$ 0.06		$ 0.11
Charges (gains) Associated with Divestitures, Per Diluted Share	0		0		(0.06)		0.20
Loss on extinguishment of debt per diluted share	0		0		0.19		0
Charges (gains) related to pension settlement per Diluted Share	0		0.13		(0.03)		0		0		0.07		0		0
Investment losses per diluted share	0		0.12		0		0
Pension and postretirement benefits mark to market adjustment, Per Diluted Share	$ 0.30		$ 0		$ 0		$ 0		0.31		0		0		0
Tax Cuts and Jobs Act of 2017, Provisional Income Tax Expense (Benefit), Per Diluted Share									0		0		0.01		0
Asset Impairment Charges, Per Diluted Share									$ 0.04		$ 0		$ 0		$ 0
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Restructuring charges, implementation costs and other related costs, net of tax									$ 0		$ (1)		$ 0		$ 1
Charges (gains) Associated with Divestitures, net of tax	$ 0		$ 0		$ (1,025)		$ 27		4		48		8		0
Pension and postretirement benefits mark to market adj, net of tax									9		0		0		0
Asset Impairment Charges, net of tax									$ 12		$ 0		$ 264		$ 11
Restructuring charges, Per Diluted Share									$ 0		$ 0		$ 0		$ 0
Charges (gains) Associated with Divestitures, Per Diluted Share	$ 0		$ 0		$ (3.37)		$ 0.09		0.01		0.16		0.03		0
Pension and postretirement benefits mark to market adjustment, Per Diluted Share									0.03		0		0		0
Asset Impairment Charges, Per Diluted Share									$ 0.04		$ 0		$ 0.87		$ 0.04

[1] The sum of individual per share amounts may not add due to rounding.

[2] Sum of the individual amounts may not add due to rounding.