XML 52 R35.htm IDEA: XBRL DOCUMENT v3.4.0.3
Significant Accounting Policies (Income Taxes) (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Schedule of Income Taxes [Line Items]    
Effective Tax Rate 26.00% 31.00%
Unrecognized Tax Benefits $ 3  
DTE Electric    
Schedule of Income Taxes [Line Items]    
Effective Tax Rate 36.00% 35.00%
Unrecognized Tax Benefits $ 4