Shareholders' equity (Details)				6 Months Ended
	May 22, 2023 shares	Aug. 04, 2022 shares	Jan. 17, 2022 shares	Jun. 30, 2023 SFr / shares shares	May 17, 2023 $ / shares	Dec. 31, 2022 SFr / shares shares	May 19, 2022 $ / shares	May 20, 2021 $ / shares
Stockholders' Equity Note [Abstract]
Common Shares, par value | SFr / shares				SFr 0.50		SFr 24.15
Treasury Stock, Shares, Retired	14,925,028	13,179,100	14,465,400	14,925,028
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures				1,781,198
Common Stock, Dividend Rate Approved | $ / shares					$ 0.86		$ 0.83	$ 0.80
Annual dividend per share approved by shareholders | $ / shares					3.44		3.32	3.20
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividend Rate Approved | $ / shares					$ 0.86		$ 0.83	$ 0.80
Treasury Stock, Shares, Retired	14,925,028	13,179,100	14,465,400	14,925,028
Treasury Stock, Common, Shares				20,760,232		31,781,758
Common Shares, par value | SFr / shares				SFr 0.50		SFr 24.15