Earnings per share - Computation for Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Income (Numerator):
Net income for basic and diluted EPS	$ 2,830	$ 746	$ (113)	$ 1,730	$ 1,379	$ 2,841	$ 3,463	$ 5,950
Shares (Denominator):
Weighted-average shares for basic EPS (in shares)	537			535			537	535
Effect of dilutive securities (in shares)	5			3			4	3
Weighted-average shares for diluted EPS (in shares)	542			538			541	538
Basic EPS (in usd per share)	$ 5.27			$ 3.23			$ 6.45	$ 11.12
Diluted EPS (in usd per share)	$ 5.22			$ 3.22			$ 6.40	$ 11.06