Supplemental financial information - Amounts reclassified out of accumulated other comprehensive income (loss), net of taxes, to net income (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 230	$ 496	$ 440
Provision for income taxes		(709)	(654)	(908)
Net income		5,001	4,799	6,510
Reclassification out of Accumulated Other Comprehensive Income | Net actuarial losses of defined benefit plans:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)	[1]	18	13	20
Provision for income taxes		(4)	(3)	(5)
Net income		14	10	15
Reclassification out of Accumulated Other Comprehensive Income | Prior service cost (credit) of defined benefit plans:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)	[1]	1	1	1
Provision for income taxes		0	0	0
Net income		$ 1	$ 1	$ 1

[1] Detailed in Note 7