Fair value measurement (Details) $ in Millions	Mar. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)
Minimum | Measurement input, discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Redeemable noncontrolling interest, measurement input	0.0608
Maximum | Measurement input, discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Redeemable noncontrolling interest, measurement input	0.0712
Carrying value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, fair value disclosure	$ 18,438	$ 17,533	$ 15,578
Fair value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, fair value disclosure	$ 18,156	$ 17,502	$ 15,342