Accounts and Notes Receivable and Credit Quality of Notes Receivable - Evaluation of Notes Receivable For Impairment (Details) (Notes receivable, USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Notes receivable	$ 199.5	$ 236.9
Ending balance individually evaluated for impairment	100.9	104.5
Ending balance collectively evaluated for impairment	98.6	132.4
Domestic
Financing Receivable, Recorded Investment, Past Due [Line Items]
Notes receivable	57.6	65.1
Ending balance individually evaluated for impairment	8.7	4.8
Ending balance collectively evaluated for impairment	48.9	60.3
International
Financing Receivable, Recorded Investment, Past Due [Line Items]
Notes receivable	141.9	171.8
Ending balance individually evaluated for impairment	92.2	99.7
Ending balance collectively evaluated for impairment	$ 49.7	$ 72.1