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Derivative financial instruments - Information about Hedged Items Included in Consolidated Balance Sheet (Detail) - Designated as Hedging Instrument - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Carrying Amount | Long-term Debt
Derivatives, Fair Value [Line Items]
Hedged item	$ 6,092	$ 5,184
Carrying Amount | Debt Securities, Available For Sale
Derivatives, Fair Value [Line Items]
Hedged item		381
Estimated Fair Value | Long-term Debt
Derivatives, Fair Value [Line Items]
Hedged item	$ 5	(155)
Estimated Fair Value | Debt Securities, Available For Sale
Derivatives, Fair Value [Line Items]
Hedged item		$ 0

X

- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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