Quarterly Results (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information [Line Items]
Sales by Company-operated restaurants	$ 8,139.2	$ 9,420.8	$ 10,012.7
Revenues from franchised restaurants	10,726.1	11,655.7	11,012.5
Total revenues	19,207.8	21,364.4	21,257.9
Total operating income	7,324.0	9,069.8	8,822.6
Net income	$ 4,730.5	$ 6,025.4	$ 5,924.3
Earnings per common share–basic	$ 6.35	$ 7.95	$ 7.61
Earnings per common share–diluted	6.31	7.88	7.54
Dividends declared per common share	$ 5.04	$ 4.73	$ 4.19
Weighted-averaged common shares–basic	744.6	758.1	778.2
Weighted-averaged common shares–diluted	750.1	764.9	785.6