Supplemental financial information - Amounts Reclassified out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 131	$ 128	$ 384	$ 327
Provision for income taxes		(192)	(213)	(500)	(731)
Net income		1,362	1,709	3,594	5,139
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]	3	4	10	12
Provision for income taxes		(1)	(1)	(3)	(3)
Net income		2	3	7	9
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	1
Provision for income taxes		0	0	0	0
Net income		$ 1	$ 1	$ 1	$ 1

[1] Detailed in Note 5