Segment Data - Schedule of Segment Data (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues from services	$ 4,584.8	$ 5,248.9	$ 12,946.1	$ 15,666.9
Franchise revenue	236.9	274.0	447.3	680.2
Franchise fees
Segment Reporting Information [Line Items]
Revenues from services	3.8	4.3	9.9	14.0
Americas
Segment Reporting Information [Line Items]
Revenues from services	929.1	1,094.5	2,776.7	3,192.9
Americas | United States
Segment Reporting Information [Line Items]
Revenues from services	578.8	666.4	1,705.6	1,942.3
Americas | United States | Franchise fees
Segment Reporting Information [Line Items]
Revenues from services	3.4	3.5	8.8	10.8
Franchise revenue	$ 116.9	$ 151.6	$ 315.7	$ 462.8