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Inventory (Tables)
3 Months Ended
Mar. 31, 2020
Inventory Disclosure [Abstract]  
Inventory Balance By Type
The following table summarizes the Company’s inventory balances as of the periods indicated (in millions):
 
March 31, 2020
 
December 31, 2019
Fuel and other raw materials
$
203

 
$
230

Spare parts and supplies
258

 
257

Total
$
461

 
$
487