Equity method investments - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		7 Months Ended	12 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Aug. 31, 2023
Schedule of Equity Method Investments [Line Items]
Gain on sale of equity method investments	$ 139	$ 969
Cencora
Schedule of Equity Method Investments [Line Items]
Outstanding shares owned (in shares)	30.5		30.5	31.8
Ownership percentage	15.30%		15.30%	15.90%
Proceeds from Sale of Equity Method Investments	$ 250	2,000
Gain on sale of equity method investments	139	969
Other comprehensive income (loss) before reclassification adjustments	$ (8)	$ (110)
Period of reporting lag	2 months
Equity investment, exceeded its proportionate share of net assets	$ 2,400		$ 2,400
Cencora | Not Designated as Hedging Instrument
Schedule of Equity Method Investments [Line Items]
Pledged collateral (in shares)			20.0	17.3
Cencora | Level 1
Schedule of Equity Method Investments [Line Items]
Fair market value of equity investment	$ 6,200		$ 6,200	$ 5,600