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                                                                   EXHIBIT 4.185

                  FOURTH AMENDMENT TO TRUST AGREEMENT BETWEEN
                     FIDELITY MANAGEMENT TRUST COMPANY AND
                           THE DETROIT EDISON COMPANY


        THIS FOURTH AMENDMENT, dated as of the first day of August, 1996, by
and between Fidelity Management Trust Company (the "Trustee") and The Detroit
Edison Company (the "Sponsor"):

                                 WITNESSETH:

        WHEREAS, the Trustee and the Sponsor heretofore entered into a Master
Trust Agreement dated June 30, 1994, with regard to The Detroit Edison Savings
& Investment Plan, The Detroit Edison Savings & Investment  Plan for Employees
Represented by Local 17 of the International  Brotherhood of Electric Workers,
and The Detroit Edison Savings &  Investment Plan for Employees Represented by
Local 223 of the Utility  Workers Union of America (collectively and
individually, the "Plan");  and
        
        WHEREAS, the Trustee and the Sponsor now desire to amend said trust
agreement as provided for in Section 14 thereof;

        NOW THEREOFRE, in consideration of the above premises the Trustee and
the Sponsor hereby amend the trust agreement by:

                (1)  Amending the "money classification" portion of Section "A"
                     by adding the following:

                     Additional Company Match

        IN WITNESS WHEREOF, the Trustee and the Sponsor have caused this Fourth
Amendment to be executed by their duly authorized officers effective  as of the
day and year first above written

THE DETROIT EDISON                FIDELITY MANAGEMENT TRUST COMPANY
COMPANY


By:     /s/                       By      /s/      7/31/96       
   -------------------------        -----------------------------      
                 7/18/96 Date                               Date