Shareholders' equity (Rollforward Of Changes In Common Stock Shares Issued And Outstanding) (Details) - shares					12 Months Ended
	May 21, 2024	May 22, 2023	Aug. 04, 2022	Jan. 17, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Shares issued, Beginning of year					431,451,586	446,376,614	474,021,114
Treasury Stock, Shares, Retired	(11,825,600)	(14,925,028)	(13,179,100)	(14,465,400)	(11,825,600)	(14,925,028)	(27,644,500)
Shares issued, End of year					419,625,986	431,451,586	446,376,614
Treasury Stock, Common, Shares					18,922,323	26,181,949	31,781,758	47,448,502
Stock Issued During Period, Shares, New Issues					2,952,591	2,500,381	2,947,272
Treasury Stock, Shares, Acquired					(7,518,565)	(11,825,600)	(14,925,028)
Shares issued and outstanding, end of year					400,703,663	405,269,637	414,594,856