Other Assets (Other Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Assets
Deferred compensation plan	$ 100.0		$ 99.9
Deferred contract costs and sales commissions	89.2		43.6
Investments	73.0		27.2
Reinsurance receivable	68.0		65.9
Amounts recoverable for capping, closure and post-closure obligations	30.5		29.9
Interest rate swaps and locks	12.8		27.1
Deferred financing costs	4.2		3.0
Other	40.1		38.6
Total	$ 417.8	$ 379.0	$ 335.2