Schedule II (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Trade Accounts Receivable [Member]
Valuation and Qualifying Accounts and Reserves [Roll Forward]
Balance at Beginning of Period		$ 1.0	$ 1.1	$ 1.1
Additions, Charged to Income		4.1	1.6	1.8
Additions, Other Charges		0.0	0.0	0.0
Deductions from Reserves	[1]	2.0	1.7	1.8
Balance at End of Period		3.1	1.0	1.1
Finance Receivables – Long-Term [Member]
Valuation and Qualifying Accounts and Reserves [Roll Forward]
Balance at Beginning of Period		0.6	0.6	0.6
Additions, Charged to Income		0.0	0.0	0.0
Additions, Other Charges		0.0	0.0	0.0
Deductions from Reserves	[1]	0.6	0.0	0.0
Balance at End of Period		0.0	0.6	0.6
Deferred Tax Assets [Member]
Valuation and Qualifying Accounts and Reserves [Roll Forward]
Balance at Beginning of Period		31.6	22.1	8.0
Additions, Charged to Income		11.4	9.5	14.1
Additions, Other Charges		0.0	0.0	0.0
Deductions from Reserves	[1]	0.0	0.0	0.0
Balance at End of Period		$ 43.0	$ 31.6	$ 22.1

[1] Includes uncollectible accounts written-off.