Shareholders' equity (Rollforward Of Changes In Common Stock Shares Issued And Outstanding) (Details) - shares					12 Months Ended
	May 22, 2023	Aug. 04, 2022	Jan. 17, 2022	Aug. 04, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Shares issued, Beginning of year					446,376,614	474,021,114	477,605,264
Treasury Stock, Shares, Retired	(14,925,028)	(13,179,100)	(14,465,400)	(3,584,150)	(14,925,028)	(27,644,500)	(3,584,150)
Shares issued, End of year					431,451,586	446,376,614	474,021,114
Treasury Stock, Common, Shares					26,181,949	31,781,758	47,448,502	26,872,639
Stock Issued During Period, Shares, New Issues					2,500,381	2,947,272	3,484,487
Treasury Stock, Shares, Acquired					(11,825,600)	(14,925,028)	(27,644,500)
Shares issued and outstanding, end of year					405,269,637	414,594,856	426,572,612