Short-Term Credit Arrangements and Borrowings (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Availability under combined facilities
Total credit facilities at December 31, 2011	$ 2,015
Amounts Outstanding
Commercial paper issuances	419
Letters of credit	218
Total amounts outstanding	637
Net availability at December 31, 2011	1,378
Unsecured letter of credit facility, expiring in December 2012 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	40
Unsecured letter of credit facility, expiering in May 2013 (Member
Availability under combined facilities
Total credit facilities at December 31, 2011	50
Unsecured letter of credit facility, expiring in August 2015[Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	125
Unsecured revolving credit facility, expiring October 26 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	1,800
DTE Energy [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	1,275
Amounts Outstanding
Commercial paper issuances	234
Letters of credit	178
Total amounts outstanding	412
Net availability at December 31, 2011	863
DTE Energy [Member] \| Unsecured letter of credit facility, expiring in December 2012 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	0
DTE Energy [Member] \| Unsecured letter of credit facility, expiering in May 2013 (Member
Availability under combined facilities
Total credit facilities at December 31, 2011	50
DTE Energy [Member] \| Unsecured letter of credit facility, expiring in August 2015[Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	125
DTE Energy [Member] \| Unsecured revolving credit facility, expiring October 26 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	1,100
Detroit Edison [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	340
Amounts Outstanding
Commercial paper issuances	0
Letters of credit	40
Total amounts outstanding	40
Net availability at December 31, 2011	300
Detroit Edison [Member] \| Unsecured letter of credit facility, expiring in December 2012 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	40
Detroit Edison [Member] \| Unsecured letter of credit facility, expiering in May 2013 (Member
Availability under combined facilities
Total credit facilities at December 31, 2011	0
Detroit Edison [Member] \| Unsecured letter of credit facility, expiring in August 2015[Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	0
Detroit Edison [Member] \| Unsecured revolving credit facility, expiring October 26 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	300
MichCon [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	400
Amounts Outstanding
Commercial paper issuances	185
Letters of credit	0
Total amounts outstanding	185
Net availability at December 31, 2011	215
MichCon [Member] \| Unsecured letter of credit facility, expiring in December 2012 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	0
MichCon [Member] \| Unsecured letter of credit facility, expiering in May 2013 (Member
Availability under combined facilities
Total credit facilities at December 31, 2011	0
MichCon [Member] \| Unsecured letter of credit facility, expiring in August 2015[Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	0
MichCon [Member] \| Unsecured revolving credit facility, expiring October 26 [Member]
Availability under combined facilities
Total credit facilities at December 31, 2011	$ 400

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References+ Details