Supplemental financial information - Amounts Reclassified out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2026	Mar. 31, 2025
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 47	$ 80
Provision for income taxes		(169)	(97)
Net income		1,545	1,179
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]	0	3
Provision for income taxes		0	(1)
Net income		0	2
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	0
Provision for income taxes		0	0
Net income		$ 1	$ 0

[1] Detailed in Note 5