Common stock (Detail)	3 Months Ended
	Mar. 31, 2024 shares
Class A [Member]
Class of Stock [Line Items]
Shares issued, beginning balance	639,328
Treasury shares, beginning balance	(71,553)
Shares outstanding, beginning balance	567,775
Conversions of Class A to Class B common stock	(400)
Conversions of Class A to Class B common stock, Outstanding	(400)
Treasury stock acquired	(4,232)
Shares issued, ending balance	638,928
Treasury shares, ending balance	(75,785)
Shares outstanding, ending balance	563,143
Class B [Member]
Class of Stock [Line Items]
Shares issued, beginning balance	1,528,152,352
Treasury shares, beginning balance	(217,590,844)
Shares outstanding, beginning balance	1,310,561,508
Conversions of Class A to Class B common stock	600,000
Conversions of Class A to Class B common stock, Outstanding	600,000
Shares issued, ending balance	1,528,752,352
Treasury shares, ending balance	(217,590,844)
Shares outstanding, ending balance	1,311,161,508