Common stock (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Class A [Member]
Class of Stock [Line Items]
Shares issued, beginning balance	665,901	678,523	719,307
Treasury shares, beginning balance	(48,788)	(34,592)	(17,337)
Shares outstanding, beginning balance	617,113	643,931	701,970
Conversions of Class A to Class B common stock	(14,451)	(12,622)	(40,784)
Conversions of Class A to Class B common stock, Outstanding	(14,451)	(12,622)	(40,784)
Treasury stock acquired	(11,098)	(14,196)	(17,255)
Shares issued, ending balance	651,450	665,901	678,523
Treasury shares, ending balance	(59,886)	(48,788)	(34,592)
Shares outstanding, ending balance	591,564	617,113	643,931
Class B [Member]
Class of Stock [Line Items]
Shares issued, beginning balance	1,488,292,852	1,469,359,852	1,408,183,852
Treasury shares, beginning balance	(197,818,349)	(119,316,381)	(23,702,319)
Shares outstanding, beginning balance	1,290,474,503	1,350,043,471	1,384,481,533
Conversions of Class A to Class B common stock	21,676,500	18,933,000	61,176,000
Conversions of Class A to Class B common stock, Outstanding	21,676,500	18,933,000	61,176,000
Treasury stock acquired	(9,896,927)	(78,501,968)	(95,614,062)
Shares issued, ending balance	1,509,969,352	1,488,292,852	1,469,359,852
Treasury shares, ending balance	(207,715,276)	(197,818,349)	(119,316,381)
Shares outstanding, ending balance	1,302,254,076	1,290,474,503	1,350,043,471