Short-Term Credit Arrangements and Borrowings (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 ratio banks percent	Dec. 31, 2011
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%
Maximum Total Funded Debt to Total Capitalization Ratio	65.00%
Maximum Total Funded Debt to Total Capitalization Ratio Denominator	100.00%
Letters of Credit Outstanding, Amount	$ 38
Borrowing Capacity Under Financing Agreement with its 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	$ 85	$ 56
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	46.00%
Total Funded Debt to Total Capitalization Ratio Denominator	100.00%