Supplemental financial information - Amounts Reclassified out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 33	$ 15	$ 55	$ 134
Provision for income taxes		(363)	(328)	(1,078)	(825)
Net income		2,295	1,947	6,787	5,631
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]	19	10	42	31
Provision for income taxes		(4)	(2)	(9)	(7)
Net income		15	8	33	24
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