Shareholders' equity - Schedule of Restricted Stock and RSU Awards (Details) - Restricted Stock and Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Shares
Unvested at beginning of year (in shares)	2,543,732,000	2,842,288,000	2,614,654,000
Granted (in shares)	2,289,278,000	949,022,000	1,282,636,000
Vested (in shares)	(1,122,923,000)	(1,118,395,000)	(899,282,000)
Canceled (in shares)	(244,707,000)	(129,183,000)	(155,720,000)
Unvested at end of year (in shares)	3,465,380,000	2,543,732,000	2,842,288,000
Weighted average fair value
Unvested at beginning of year (in dollars per share)	$ 17.80	$ 15.11	$ 13.09
Granted (in dollars per share)	16.09	21.90	17.83
Vested (in dollars per share)	16.41	14.62	13.21
Canceled (in dollars per share)	17.78	16.39	14.56
Unvested at end of year (in dollars per share)	$ 17.12	$ 17.80	$ 15.11