Segment Data - Schedule of Segment Data (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues from services	$ 5,373.1	$ 5,656.9	$ 10,418.0	$ 11,179.3
Franchise revenue	163.2	273.9	406.2	510.7
Franchise
Segment Reporting Information [Line Items]
Revenues from services	4.1	6.2	9.7	11.4
Americas
Segment Reporting Information [Line Items]
Revenues from services	1,043.4	1,052.5	2,050.7	2,075.1
Americas | United States
Segment Reporting Information [Line Items]
Revenues from services	630.9	640.5	1,234.5	1,256.8
Americas | United States | Franchise
Segment Reporting Information [Line Items]
Revenues from services	3.7	3.9	7.3	7.1
Franchise revenue	$ 154.3	$ 166.7	$ 311.2	$ 315.7