Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements and Derivatives (Detail Textuals)

v3.6.0.2
Fair Value Measurements and Derivatives (Detail Textuals)
Metric_Ton in Millions, $ in Millions, € in Billions
Dec. 31, 2016
USD ($)
Metric_Ton
Dec. 31, 2016
EUR (€)
Metric_Ton
Dec. 31, 2015
USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Fair value of long-term debt $ 6,525.7   $ 6,495.5
Fair value of long-term debt in excess of carrying value $ 11.6   $ 6.6
Fuel Swaps      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Projected fuel purchases | Metric_Ton 1.5 1.5  
Foreign currency collar      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Notional amount of derivatives $ 2,700.0 € 2.6  
Interest rates swaps      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Notional amount of derivatives $ 308.5