Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details)

v3.8.0.1
DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net $ 41.2 $ 11.6 $ 89.7 $ 49.7
Customer Supply Agreements [Member] | Product Revenues [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net 54.3 7.1 123.9 26.8
Provisional Pricing Arrangements [Member] | Product Revenues [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (13.1) 4.5 (32.9) 22.9
Commodity Contract [Member] | Other Nonoperating Income (Expense) [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net $ 0.0 $ 0.0 $ (1.3) $ 0.0