Short-Term Credit Arrangements and Borrowings (Details Textuals) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 300
Revolving Credit Facilities with a Syndicate Number of Banks	20
Number of Banks that Provide Percentage of Commitment in any Facility	1
Maximum Percentage of Commitment to Bank in any Facility	8.50%
Maximum Total Funded Debt to Total Capitalization Ratio	0.65
Maximum Total Funded Debt to Total Capitilization Ration Denominator	1
Total Funded Debt to Total Capitalization Ratio	0.52
Total Funded Debt to Total Capitalization Ratio Denominator	1
Short-term Debt, Weighted Average Interest Rate	0.40%
DTE Electric [Member]
Short-term Debt [Line Items]
Long-term Commercial Paper, Current	$ (130)	$ 0