Short-Term Credit Arrangements and Borrowings (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Line Of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	$ 286
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	1,975
Commercial paper issuances	98
Line of Credit, Current	188
Net availability at September 30, 2012	1,689
Unsecured letter of credit facility, expiring in May 2013 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	50
Unsecured letter of credit facility, expiring in August 2015 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	125
Unsecured revolving credit facility, expiring October 2016 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	1,800
DTE Energy [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	188
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	1,275
Commercial paper issuances	0
Line of Credit, Current	188
Net availability at September 30, 2012	1,087
DTE Energy [Member] \| Unsecured letter of credit facility, expiring in May 2013 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	50
DTE Energy [Member] \| Unsecured letter of credit facility, expiring in August 2015 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	125
DTE Energy [Member] \| Unsecured revolving credit facility, expiring October 2016 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	1,100
Detroit Edison [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	0
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	300
Commercial paper issuances	0
Line of Credit, Current	0
Net availability at September 30, 2012	300
Detroit Edison [Member] \| Unsecured letter of credit facility, expiring in May 2013 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	0
Detroit Edison [Member] \| Unsecured letter of credit facility, expiring in August 2015 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	0
Detroit Edison [Member] \| Unsecured revolving credit facility, expiring October 2016 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	300
MichCon [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	98
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	400
Commercial paper issuances	98
Line of Credit, Current	0
Net availability at September 30, 2012	302
MichCon [Member] \| Unsecured letter of credit facility, expiring in May 2013 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	0
MichCon [Member] \| Unsecured letter of credit facility, expiring in August 2015 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	0
MichCon [Member] \| Unsecured revolving credit facility, expiring October 2016 [Member]
Availability Under Combined Facilities
Total credit facilities at September 30, 2012	$ 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