Fair value measurement - Summary of Financial Instrument Measured on a Basis Other Than Fair Value (Detail) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 16,185	$ 16,929
Senior notes and sustainability-linked senior notes included under senior notes and loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	12,152	15,128
Senior notes and convertible senior debentures included under short-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 4,033	$ 1,801

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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