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Jointly-Owned Utility Plant (Ownership Information) (Details) - DTE Electric
$ in Millions
Dec. 31, 2019
USD ($)
MW
Belle River  
Jointly-Owned Utility Plant Interests [Line Items]  
Total plant capacity | MW 1,270
Ownership interest 81.00%
Investment in Property, plant, and equipment (in millions) $ 1,903
Accumulated depreciation (in millions) $ 896
Ludington Hydroelectric Pumped Storage  
Jointly-Owned Utility Plant Interests [Line Items]  
Total plant capacity | MW 2,220
Ownership interest 49.00%
Investment in Property, plant, and equipment (in millions) $ 616
Accumulated depreciation (in millions) $ 193