Segment Reporting - Revenues by Operating Segment and Country (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Major Customer [Line Items]
Total revenues	$ 1,343.4	$ 1,132.7	$ 2,597.2	$ 2,133.3
Canada
Revenue, Major Customer [Line Items]
Total revenues	745.3	687.9	1,437.7	1,344.9
United States
Revenue, Major Customer [Line Items]
Total revenues	450.8	313.2	871.5	545.6
Other
Revenue, Major Customer [Line Items]
Total revenues	147.3	131.6	288.0	242.8
Tim Hortons brand
Revenue, Major Customer [Line Items]
Total revenues	823.0	772.3	1,586.5	1,505.9
Burger King brand
Revenue, Major Customer [Line Items]
Total revenues	418.1	293.7	808.0	560.7
Popeyes brand
Revenue, Major Customer [Line Items]
Total revenues	102.3	$ 66.7	202.7	$ 66.7
Amounts Under Previous Standards
Revenue, Major Customer [Line Items]
Total revenues	1,144.3		2,216.1
Amounts Under Previous Standards | Tim Hortons brand
Revenue, Major Customer [Line Items]
Total revenues	770.3		1,482.1
Amounts Under Previous Standards | Burger King brand
Revenue, Major Customer [Line Items]
Total revenues	306.2		599.0
Amounts Under Previous Standards | Popeyes brand
Revenue, Major Customer [Line Items]
Total revenues	$ 67.8		$ 135.0