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Significant Accounting Policies (Details Textuals) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Dec. 31, 2014
Significant Accounting Policies [Line Items]          
Other income $ 49 $ 40 $ 100 $ 81  
Increase (decrease) in effective tax rate from prior year (8.00%)   (3.00%)    
Deferred tax expense     $ 8    
Unrecognized tax benefits that would impact effective tax rate $ 2   2    
Decrease in unrecognized tax benefits 6   6    
DTE Electric          
Significant Accounting Policies [Line Items]          
Other income $ 13 17 $ 28 30  
Increase (decrease) in effective tax rate from prior year (2.00%)   (2.00%)    
DTE Electric | DTE Energy          
Significant Accounting Policies [Line Items]          
Income tax receivable $ 49   $ 49   $ 29
Minimum          
Significant Accounting Policies [Line Items]          
Finite-lived intangible asset, useful life     1 year    
Maximum          
Significant Accounting Policies [Line Items]          
Finite-lived intangible asset, useful life     26 years    
Power and Industrial Projects          
Significant Accounting Policies [Line Items]          
Other income $ 20 $ 15 $ 39 $ 32