Goodwill and Other Intangible Assets - Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 1,315.6	$ 1,343.0
Finite-lived:
Gross	466.0	472.9
Accumulated Amortization	360.9	339.9
Net	105.1	133.0
Indefinite-lived:
Gross	150.9	151.0
Net	150.9	151.0
Total intangible assets
Gross	616.9	623.9
Accumulated Amortization	360.9	339.9
Net	256.0	284.0
Accumulated impairment loss	513.4	513.4
Intangible Assets, Future Amortization Expense by Fiscal Year [Abstract]
Estimated amortization expense, remainder of 2018	8.5
Estimated amortization expense, 2019	29.2
Estimated amortization expense, 2020	24.4
Estimated amortization expense, 2021	13.6
Estimated amortization expense, 2022	10.0
Estimated amortization expense, 2023	7.8
Tradenames
Indefinite-lived:
Gross	52.0	52.0
Net	52.0	52.0
Accumulated impairment loss	139.5	139.5
Reacquired franchise rights
Indefinite-lived:
Gross	98.9	99.0
Net	98.9	99.0
Customer relationships
Finite-lived:
Gross	447.6	453.6
Accumulated Amortization	345.2	325.2
Net	102.4	128.4
Other
Finite-lived:
Gross	18.4	19.3
Accumulated Amortization	15.7	14.7
Net	$ 2.7	$ 4.6