Acquisitions and other investments - Schedule of Purchase Price Allocation and Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Nov. 24, 2021	Oct. 29, 2021	Feb. 28, 2022	Aug. 31, 2021
Identifiable assets acquired and liabilities assumed:
Goodwill			$ 21,958	$ 12,421
VillageMD
Purchase Price Allocation:
Total purchase price	$ 5,200
Less: purchase price for issuance of new preferred units at fair value	(2,300)
Net consideration	2,900
Fair value of share-based compensation awards attributable to pre-combination services	683
Fair value of previously held equity interests	3,211
Fair value of non-controlling interests	3,257
Total	10,051
Identifiable assets acquired and liabilities assumed:
Tangible assets	734
Intangible assets	1,621
Liabilities	(340)
Total identifiable net assets	2,016
Goodwill	8,036
Cash consideration for preferred units	1,100
Promissory note	$ 1,200
Shields Health Solutions Parent, LLC
Purchase Price Allocation:
Cash consideration		$ 969
Fair value of share-based compensation awards attributable to pre-combination services		13
Fair value of previously held equity interests		502
Fair value of non-controlling interests		589
Total		2,074
Identifiable assets acquired and liabilities assumed:
Tangible assets		84
Intangible assets		1,060
Liabilities		(528)
Total identifiable net assets		616
Goodwill		$ 1,457