Accounts Receivable, Net of Allowance (Schedule of Activity, Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Rollforward]
Allowance for doubtful accounts at beginning of year	$ 13.9	$ 15.7
Provision for doubtful accounts	2.1	1.8
Amounts charged against the allowance	(8.3)	(3.6)
Allowance for doubtful accounts at end of year	$ 7.7	$ 13.9