Earnings per share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Income (Numerator):
Net income for basic and diluted EPS	$ 2,143	$ 1,317	$ 1,476	$ 1,884	$ 464	$ 1,646	$ 4,936	$ 3,994
Shares (Denominator):
Weighted-average shares for basic EPS (in shares)	535			567			539	572
Effect of dilutive securities (in shares)	3			3			3	4
Weighted-average shares for diluted EPS (in shares)	538			570			542	576
Basic EPS (in usd per share)	$ 4.01			$ 3.32			$ 9.16	$ 6.98
Diluted EPS (in usd per share)	$ 3.98			$ 3.31			$ 9.11	$ 6.93