Goodwill and other intangible assets - Intangible assets - Narrative (Detail) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible asset amortization expense	$ 1.8	$ 1.8	$ 1.2
Estimated amortization expense - 2025	1.7
Estimated amortization expense - 2026	1.6
Estimated amortization expense - 2027	1.4
Estimated amortization expense - 2028	1.4
Estimated amortization expense - 2029	1.3
Intangible assets with indefinite lives, excluding goodwill	$ 18.9	$ 18.9