Supplemental financial information - Amounts Reclassified out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 128	$ 33	$ 327	$ 55
Provision for income taxes		(213)	(363)	(731)	(1,078)
Net income		1,709	2,295	5,139	6,787
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]	4	19	12	42
Provision for income taxes		(1)	(4)	(3)	(9)
Net income		3	15	9	33
Reclassification out of Accumulated Other Comprehensive Income | Prior service 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