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Goodwill and other intangible assets - additional information (Details) $ in Millions	3 Months Ended			12 Months Ended
	Aug. 31, 2020 USD ($) store	May 31, 2020 USD ($) store	Aug. 31, 2019 USD ($)	Aug. 31, 2020 USD ($) store	Aug. 31, 2019 USD ($)	Aug. 31, 2018 USD ($) store	Jun. 01, 2020	Jun. 01, 2019
Goodwill [Line Items]
Number of reporting segments included in impairment analysis \| store		2
Goodwill impairment loss				$ 1,675
Goodwill	$ 15,268		$ 16,560	15,268	$ 16,560	$ 16,914
Indefinite lived intangible assets	7,416		7,110	7,416	7,110
Impairment of definite-lived intangible assets	$ 47
Goodwill acquired during period				62	8
Amortization expense for intangible assets				461	552	$ 493
Rite Aid Corporation - Second And Third Distribution Center
Goodwill [Line Items]
Payments to acquire business				91
Goodwill acquired during period				$ 62
Rite Aid Corporation
Goodwill [Line Items]
Goodwill			1,331		1,331
Number of stores acquired \| store						1,932
Decrease in goodwill from purchase accounting adjustments					13
Minimum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)							4.00%
Minimum \| Rite Aid Corporation
Goodwill [Line Items]
Number of stores acquired \| store	2			2
Maximum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)							239.00%
Maximum \| Rite Aid Corporation
Goodwill [Line Items]
Number of stores acquired \| store	3			3
Pharmacy licenses
Goodwill [Line Items]
Indefinite lived intangible assets	$ 2,028		1,878	$ 2,028	$ 1,878
Boots Reporting Unit
Goodwill [Line Items]
Goodwill impairment loss		$ 1,700
Impairment of intangible assets		$ 300
Goodwill	1,100			1,100
Indefinite lived intangible assets	$ 7,200			$ 7,200
Boots Reporting Unit \| Trade names \| Minimum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)	4.00%			4.00%
Boots Reporting Unit \| Trade names \| Maximum
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)	31.00%			31.00%
Boots Reporting Unit \| Pharmacy licenses
Goodwill [Line Items]
Impairment of intangible assets	$ 73		$ 73
Other International Reporting Unit
Goodwill [Line Items]
Reporting unit fair value in excess of carrying amount (as a percent)							4.00%	16.00%
Goodwill	$ 500			$ 500