Goodwill And Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization expense for acquired intangible assets	$ 21.9	$ 15.7	$ 11.8
Client Contracts And Broker Relationships | Ceridian Channel Partner Arrangement
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	20.9
Client Contracts And Broker Relationships | ADP/COBRA/CHSA
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 93.9