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Derivative financial instruments - Information about Fair Values of Derivative Instruments in Consolidated Statement of Income (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivatives not designated as hedging instruments, derivatives | $ 9 | $ 7 | $ 18 | $ 14
Interest rate swap agreements | Fixed Rate Long-Term Borrowings | Designated as Hedging Instrument | Fair value hedges: |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative, gain (loss), statement of income or comprehensive income [extensible enumeration] | Other costs of operations | Other costs of operations | Other costs of operations | Other costs of operations
Derivatives in fair value hedging relationships, derivative | $ 54 | $ (18) | $ 147 | $ (78)
Derivatives in fair value hedging relationships, hedged item | (55) | 18 | (147) | 78
Interest Rate Contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivatives not designated as hedging instruments, derivatives | 7 | 3 | 12 | 6
Foreign exchange and other option and futures contracts |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivatives not designated as hedging instruments, derivatives | $ 2 | $ 4 | $ 6 | $ 8

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- Definition Line items represent financial concepts included in a table. 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