Fair value measurement (Details) $ in Millions	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)
Minimum | Measurement input, discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Redeemable noncontrolling interest, measurement input	0.0610
Maximum | Measurement input, discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Redeemable noncontrolling interest, measurement input	0.0713
Carrying value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, fair value disclosure	$ 18,579	$ 13,851	$ 13,737
Fair value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, fair value disclosure	$ 18,584	$ 13,604	$ 13,599