Accounts Receivable, Net of Allowance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Non-Recourse Arrangement [Member]
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Improvement in cash collections from non-recourse financing arrangement	$ 12.0	$ 70.0
Uncollectible Receivables [Member]
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Change in estimate, provision for doubtful accounts		$ 0.5
Interest Expense [Member] | Financing Receivable, Non-Recourse Arrangement [Member]
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Non-recourse financing arrangement, discount charge	$ 1.6