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MATERIALS, SUPPLIES, AND INVENTORIES
6 Months Ended
Jun. 30, 2021
Inventory Disclosure [Abstract]  
MATERIALS, SUPPLIES, AND INVENTORIES MATERIALS, SUPPLIES, AND INVENTORIES
Our inventory consisted of:
(in millions)June 30, 2021December 31, 2020
Materials and supplies$218.9 $218.1 
Natural gas in storage162.1 224.9 
Fossil fuel71.7 85.6 
Total$452.7 $528.6 

PGL and NSG price natural gas storage injections at the calendar year average of the costs of natural gas supply purchased. Withdrawals from storage are priced on the LIFO cost method. For interim periods, the difference between current projected replacement cost and the LIFO cost for quantities of natural gas temporarily withdrawn from storage is recorded as a temporary LIFO liquidation debit or credit. At June 30, 2021, we had a temporary LIFO liquidation credit of $26.7 million recorded within other current liabilities on our balance sheet. Due to seasonality requirements, PGL and NSG expect these interim reductions in LIFO layers to be replenished by year end.

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