1 EXHIBIT 15.6 [DELOITTE & TOUCHE LLP LETTERHEAD] DTE Energy Company and The Detroit Edison Company Detroit, Michigan We have made reviews, in accordance with standards established by the American Institute of Certified Public Accountants, of the unaudited interim financial information of DTE Energy Company and subsidiary companies and of The Detroit Edison Company and subsidiary companies for the three-month and nine-month periods ended September 30, 1997 and 1996, as indicated in our report dated October 27, 1997. Because we did not perform an audit, we expressed no opinion on that information. We are aware that our report referred to above, which is included in your Quarterly Report on Form 10-Q for the quarter ended September 30, 1997, is incorporated by reference in the following Registration Statements: REGISTRATION FORM NUMBER DTE Energy Company Form S-3 33-57545 Form S-8 333-00023 The Detroit Edison Company Form S-3 33-53207 Form S-3 33-64296 We also are aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1933, is not considered a part of the Registration Statement which is prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of that Act. Deloitte & Touche LLP October 27, 1997