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v3.19.3.a.u2

Summary of Significant Accounting Policies Materials, Supplies, and Inventories (Details) $ in Millions | Dec. 31, 2019 USD ($) $ / Dekatherm | Dec. 31, 2018 USD ($) $ / Dekatherm
--- | --- | ---
Inventory |  |
Materials and supplies | $ 234.2 | $ 226.6
Natural gas in storage | 227.7 | 232.9
Fossil fuel | 87.9 | 88.7
Total | $ 549.8 | $ 548.2
Percentage of LIFO inventory | 19.00% | 16.00%
PGL and NSG |  |
Inventory |  |
Excess of replacement or current costs over stated LIFO value | $ 9.8 | $ 72.4
Natural gas price benchmark | $ / Dekatherm | 1.95 | 3.08

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