Derivative financial instruments - Summary of Operating Currency Hedging Instruments (Details) - Jun. 30, 2026 € in Millions, R$ in Millions	EUR (€)	BRL (R$)
Notional amount
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	€ 11,575
Notional amount \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	6,536
Notional amount \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2,968
Notional amount \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	555
Notional amount \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	530
Notional amount \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	422
Notional amount \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	224
Notional amount \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	5,039
Notional amount \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	3,200
Notional amount \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	596
Notional amount \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	306
Notional amount \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	120
Notional amount \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	120
Notional amount \| Cash flow hedges
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	221
Notional amount \| Cash flow hedges \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	221
Notional amount \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	221
Notional amount \| Cash flow hedges \| of which Brazilian real \| Medley
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place \| R$		R$ 1,300
Notional amount \| Cash flow hedges \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Cash flow hedges \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Notional amount \| Not eligible for hedge accounting
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	11,354
Notional amount \| Not eligible for hedge accounting \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	6,315
Notional amount \| Not eligible for hedge accounting \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2,968
Notional amount \| Not eligible for hedge accounting \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	555
Notional amount \| Not eligible for hedge accounting \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	530
Notional amount \| Not eligible for hedge accounting \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	201
Notional amount \| Not eligible for hedge accounting \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	224
Notional amount \| Not eligible for hedge accounting \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	5,039
Notional amount \| Not eligible for hedge accounting \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	3,200
Notional amount \| Not eligible for hedge accounting \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	596
Notional amount \| Not eligible for hedge accounting \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	306
Notional amount \| Not eligible for hedge accounting \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	120
Notional amount \| Not eligible for hedge accounting \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	120
Fair value
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(33)
Fair value \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(66)
Fair value \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(38)
Fair value \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(6)
Fair value \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(9)
Fair value \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(3)
Fair value \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	33
Fair value \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	24
Fair value \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2
Fair value \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2
Fair value \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	6
Fair value \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	1
Fair value \| Cash flow hedges
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Fair value \| Cash flow hedges \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Fair value \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Fair value \| Cash flow hedges \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Cash flow hedges \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Not eligible for hedge accounting
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(25)
Fair value \| Not eligible for hedge accounting \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(58)
Fair value \| Not eligible for hedge accounting \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(38)
Fair value \| Not eligible for hedge accounting \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Fair value \| Not eligible for hedge accounting \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(6)
Fair value \| Not eligible for hedge accounting \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(1)
Fair value \| Not eligible for hedge accounting \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(3)
Fair value \| Not eligible for hedge accounting \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	33
Fair value \| Not eligible for hedge accounting \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	24
Fair value \| Not eligible for hedge accounting \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2
Fair value \| Not eligible for hedge accounting \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	2
Fair value \| Not eligible for hedge accounting \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	6
Fair value \| Not eligible for hedge accounting \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	1
Value of hedge recognized in equity \| Cash flow hedges
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Value of hedge recognized in equity \| Cash flow hedges \| Forward currency sales
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Value of hedge recognized in equity \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Brazilian real
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	(8)
Value of hedge recognized in equity \| Cash flow hedges \| of which Saudi Arabian riyal
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| Forward currency purchases
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which US dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Singapore dollar
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Chinese yuan renminbi
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which Turkish lira
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	0
Value of hedge recognized in equity \| Cash flow hedges \| of which United Arab Emirates dirham
Disclosure of Information about Credit Exposures Designated as Measured at Fair Value Through Profit or Loss [Line Items]
Operating currency hedging instruments in place	€ 0