Income taxes - Narrative (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Income Tax Disclosure [Abstract] | ||
| Income Tax Examination, Year under Examination | 2014 2015 2016 2017 2018 2019 2020 | |
| Income tax liabilities with federal taxing authority settled through year | 2013 | |
| Income tax liabilities with state and foreign jurisdictions estimated settlement year | 2026 | |
| Unrecognized tax benefits | $ 456 | $ 501 |
| Unrecognized tax benefits that would impact effective tax rate | $ 421 |