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Organization and Basis of Presentation (Details)
customer in Millions
Dec. 31, 2017
USD ($)
customer
Dec. 31, 2016
USD ($)
Oct. 01, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]      
Number of electric utility customers | customer 2.2    
Number of gas utility customers | customer 1.3    
Error Corrections and Prior Period Adjustments Restatement [Line Items]      
Significant potential exposure $ 0    
Amount in excess of carrying amount 72,000,000 $ 73,000,000  
DTE Electric      
Error Corrections and Prior Period Adjustments Restatement [Line Items]      
Significant potential exposure $ 0    
NEXUS Pipeline      
Error Corrections and Prior Period Adjustments Restatement [Line Items]      
Ownership interest 50.00%    
West Virginia | Midstream natural gas gathering assets      
Error Corrections and Prior Period Adjustments Restatement [Line Items]      
Percentage of voting interests acquired 55.00%   55.00%