Earnings per share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income (Numerator):
Net income for basic and diluted EPS	$ 1,476	$ 1,646
Shares (Denominator):
Weighted-average shares for basic EPS (in shares)	548	577
Effect of dilutive securities (in shares)	3	4
Weighted-average shares for diluted EPS (in shares)	551	581
Basic EPS (in usd per share)	$ 2.69	$ 2.85
Diluted EPS (in usd per share)	$ 2.68	$ 2.83