Variable interest entities - Schedule of results of variable interest entities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Variable Interest Entity [Line Items]
Gross profit	$ 3,675	$ 3,630	$ 5,482	$ 5,249
Net loss	1,297	1,199	1,413	1,171
Net cash (used in) provided by operating activities			773	963
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Total revenues	98	122	194	237
Total cost of revenues	(89)	(113)	(176)	(227)
Gross profit	9	9	18	10
Net loss	$ (3)	$ (6)	(12)	(18)
Net cash (used in) provided by operating activities			$ (2)	$ 6