Short-Term Credit Arrangements and Borrowings (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years ratio banks percent	Dec. 31, 2010 percent
Short-term Debt [Line Items]
Revolving Credit Facilities with a Syndicate Number of Banks	20
Maximum Percentage of Commitment to Bank in any Facility	8.50%
Renewal of Credit Facility Time Period	5
Maximum Total Funded Debt to Total Capitalization Ratio	65.00%
Maximum Total Funded Debt to Total Capitilization Ration Denominator	100.00%
Letters of Credit Outstanding, Amount	$ 39
Short-term Debt, Weighted Average Interest Rate	0.50%	0.40%
Borrowing Capacity Under Financing Agreement With iss Clearing Agent	100
Maximum Additional Margin Financing	50
Line of Credit Facility, Increase, Additional Borrowings	15
Line of Credit Facility Current Borrowing	115
Other Short-term Borrowings	$ 56	$ 39
DTE Energy [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	50.00%
Total Funded Debt to Total Capitalization Ratio Denominator	100.00%
Detroit Edison [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	52.00%
Total Funded Debt to Total Capitalization Ratio Denominator	100.00%
MichCon [Member]
Short-term Debt [Line Items]
Total Funded Debt to Total Capitalization Ratio	45.00%
Total Funded Debt to Total Capitalization Ratio Denominator	100.00%