Need a way to find if a range of cells in Excel contains a formula rather than static numerical data.?

So I have a terribly long spreadsheet (about 19,000 rows), and I've used the Subtotals command to, well, to return subtotals for customers...what I'd like to do now is to have a separate column where ONLY the subtotals appear, without all the individual customer transaction data. In other words, all the individual data cells are raw data, but the subtotal cells are formulaic. Is there an IF function I can use to return the values of JUST the cells that contain formulae (subtotals)? If all the data, including subtotals appears in column F, is there an easier way to make the subtotals appear by themselves in column G without using a complicated IF function? Thanks for your help.