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Inventory
 12 Months Ended
Dec. 31, 2019
Inventories [Abstract]  
Inventory
Inventory
 
 
2019


2018

Product inventory
 
$
468


$
297

Materials and supplies
 
684


658

 
 
$
1,152

 
$
955


The Company recorded a write-down of its product inventory of $4 million from cost to net realizable value as at December 31, 2019 (2018 – $13 million).