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MATERIALS, SUPPLIES, AND INVENTORIES
 9 Months Ended
Sep. 30, 2019
Inventory Disclosure [Abstract]  
MATERIALS, SUPPLIES, AND INVENTORIES MATERIALS, SUPPLIES, AND INVENTORIES

Our inventory consisted of:
(in millions)
 
September 30, 2019
 
December 31, 2018
Materials and supplies
 
$
150.0

 
$
146.1

Fossil fuel
 
52.6

 
58.7

Natural gas in storage
 
34.4

 
36.6

Total
 
$
237.0

 
$
241.4



Substantially all materials and supplies, fossil fuel, and natural gas in storage inventories are recorded using the weighted-average cost method of accounting.