Goodwill and Other Intangible Assets, Net - Other Intangible Assets, Net (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Gross Intangible Assets
Beginning balance	$ 793.7
Acquisitions	29.9
Adjustments and Other	(5.2)
Ending balance	818.4
Accumulated Amortization
Beginning balance	(687.2)
Additions Charged to Expense	(9.8)
Adjustments and Other	4.4
Ending balance	(692.6)
Other Intangible Assets, Net	125.8	$ 106.5
Customer relationships, franchise and other municipal agreements
Gross Intangible Assets
Beginning balance	692.4
Acquisitions	23.6
Adjustments and Other	0.0
Ending balance	716.0
Accumulated Amortization
Beginning balance	(607.2)
Additions Charged to Expense	(7.6)
Adjustments and Other	0.2
Ending balance	(614.6)
Other Intangible Assets, Net	101.4
Non-compete agreements
Gross Intangible Assets
Beginning balance	37.0
Acquisitions	6.3
Adjustments and Other	0.9
Ending balance	44.2
Accumulated Amortization
Beginning balance	(31.5)
Additions Charged to Expense	(1.8)
Adjustments and Other	0.0
Ending balance	(33.3)
Other Intangible Assets, Net	10.9
Other intangible assets
Gross Intangible Assets
Beginning balance	64.3
Acquisitions	0.0
Adjustments and Other	(6.1)
Ending balance	58.2
Accumulated Amortization
Beginning balance	(48.5)
Additions Charged to Expense	(0.4)
Adjustments and Other	4.2
Ending balance	(44.7)
Other Intangible Assets, Net	$ 13.5