Supplemental financial information - Amounts Reclassified out of AOCI (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net (OI&E)		$ 15	$ 46
Provision for income taxes		(325)	(186)
Net income		2,201	1,753
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	11
Provision for income taxes		(1)	(3)
Net income		$ 2	$ 8

[1] Detailed in Note 5.