Goodwill and other intangible assets - Intangible assets - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible asset amortization expense	$ 446	$ 444
Intangible assets with indefinite lives, excluding goodwill	$ 19,000		$ 18,900

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets.

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