As far as I know there is no functionality that retains formatting when exporting Access reports to Excel. But you can create Excel spreadsheets from Access.
What you can do is set up the formatting in Excel. How to do that is to start a macro recorder and build the formatting in a spreadsheet and when finished, stop the recorder and save the macro. Then you go into the macro's code, copy the VBA and paste that into an Access module, with the code to move the data to the spreadsheet. You are going to have to perform loops, count lines and use at least one recordset to move the data into the spreadsheet that way.
Do a search for automating Excel from Access and you should find some good examples.