Income taxes - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Income tax liabilities with federal taxing authority settled through year	2011
Income tax liabilities with state and foreign jurisdictions estimated settlement year	2024
Unrecognized tax benefits	$ 480	$ 440
Unrecognized tax benefits that would impact effective tax rate	$ 420
Earliest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2014
Latest Tax Year [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2019
Tax Year 2012 [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2012
Tax Year 2013 [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2013