Short-Term Credit Arrangements and Borrowings (Details) (USD $) In Millions	Sep. 30, 2011
Availability under combined facilities
Total credit facilities at September 30, 2011	$ 1,975
Amounts Outstanding
Commercial paper issuances	275
Letters of credit outstanding at September 30, 2011	144
Total amounts outstanding	419
Net availability at September 30, 2011	1,556
DTE Energy [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	1,275
Amounts Outstanding
Commercial paper issuances	126
Letters of credit outstanding at September 30, 2011	144
Total amounts outstanding	270
Net availability at September 30, 2011	1,005
DTE Energy [Member] \| Unsecured Revolving Facility 1 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	538
DTE Energy [Member] \| Unsecured Revolving Facility 2 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	562
DTE Energy [Member] \| Unsecured Revolving Facility 3 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	50
DTE Energy [Member] \| Unsecured Revolving Facility 4 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	125
Subsidiary 1 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	275
Amounts Outstanding
Commercial paper issuances	49
Letters of credit outstanding at September 30, 2011	0
Total amounts outstanding	49
Net availability at September 30, 2011	226
Subsidiary 1 [Member] \| Unsecured Revolving Facility 1 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	212
Subsidiary 1 [Member] \| Unsecured Revolving Facility 2 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	63
Subsidiary 1 [Member] \| Unsecured Revolving Facility 3 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	0
Subsidiary 1 [Member] \| Unsecured Revolving Facility 4 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	0
Subsidiary 2 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	425
Amounts Outstanding
Commercial paper issuances	100
Letters of credit outstanding at September 30, 2011	0
Total amounts outstanding	100
Net availability at September 30, 2011	325
Subsidiary 2 [Member] \| Unsecured Revolving Facility 1 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	250
Subsidiary 2 [Member] \| Unsecured Revolving Facility 2 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	175
Subsidiary 2 [Member] \| Unsecured Revolving Facility 3 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	0
Subsidiary 2 [Member] \| Unsecured Revolving Facility 4 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	0
Unsecured Revolving Facility 1 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	1,000
Unsecured Revolving Facility 2 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	800
Unsecured Revolving Facility 3 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	50
Unsecured Revolving Facility 4 [Member]
Availability under combined facilities
Total credit facilities at September 30, 2011	$ 125

- 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