Goodwill and other intangible assets - Intangible assets - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible asset amortization expense	$ 444	$ 435
Intangible assets with indefinite lives, excluding goodwill	$ 18,900		$ 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. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 350
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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