Short-Term Credit Arrangements and Borrowings (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Availability under combined facilities
Total credit facilities	$ 1,975
Commercial Paper	216
Amounts Outstanding
Letters of credit	184
Total amounts outstanding	400
Net availability	1,575
Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	50
Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	125
Unsecured revolving credit facility [Member]
Availability under combined facilities
Total credit facilities	1,800
DTE Energy [Member]
Availability under combined facilities
Total credit facilities	1,375
Commercial Paper	101
Amounts Outstanding
Letters of credit	184
Total amounts outstanding	285
Net availability	1,090
DTE Energy [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	50
DTE Energy [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	125
DTE Energy [Member] \| Unsecured revolving credit facility [Member]
Availability under combined facilities
Total credit facilities	1,200
DTE Electric [Member]
Availability under combined facilities
Total credit facilities	300
Commercial Paper	96
Amounts Outstanding
Letters of credit	0
Total amounts outstanding	96
Net availability	204
DTE Electric [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	0
DTE Electric [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	0
DTE Electric [Member] \| Unsecured revolving credit facility [Member]
Availability under combined facilities
Total credit facilities	300
DTE Gas [Member]
Availability under combined facilities
Total credit facilities	300
Commercial Paper	19
Amounts Outstanding
Letters of credit	0
Total amounts outstanding	19
Net availability	281
DTE Gas [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	0
DTE Gas [Member] \| Unsecured letter of credit facility [Member]
Availability under combined facilities
Total credit facilities	0
DTE Gas [Member] \| Unsecured revolving credit facility [Member]
Availability under combined facilities
Total credit facilities	$ 300

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

+ References+ Details

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