Other Operating Expenses (Income), net - Other Operating Expenses (Income), Net (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Net losses (gains) on disposal of assets, restaurant closures, and refranchisings	$ 3.4	$ 3.3	$ 14.9	$ 19.6
Litigation settlements and reserves, net	0.6	0.4	1.7	2.0
Net losses (gains) on foreign exchange	17.7	4.1	64.9	16.1
Other, net	(0.2)	0.9	0.6	0.5
Other operating expenses (income), net	$ 21.5	$ 8.7	$ 82.1	$ 38.2