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Property, Plant, and Equipment (Capitalized Software) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Property, Plant, and Equipment [Line Items]      
Amortization expense of capitalized software $ 123 $ 108 $ 101
Gross carrying value of capitalized software 906 905  
Accumulated amortization of capitalized software 520 534  
DTE Electric      
Property, Plant, and Equipment [Line Items]      
Amortization expense of capitalized software 112 101 $ 93
Gross carrying value of capitalized software 811 799  
Accumulated amortization of capitalized software $ 462 $ 463