Report showing where my cash is (Q Mac)

Actually, this is relatively easy to accomplish. Click on Investing in the left sidebar. (Or just Brokerage or Retirement, if you want those subsets of your investments.) Click on the Portfolio tab. Set the first filter to "Portfolio Value" and the second filter to "By Account". The Portfolio will show the values of each of your accounts.

If you click Print (now stupidly hidden behind the circular ••• icon on the right side above the graph), you can print to paper, or simply open in Preview, and the report will show each of your accounts an under them the holdings in each security — including cash — in that account.

You can also see this on-screen without printing, but you need to click the little triangle to the left of each account to open its details. If you have 6 or 8 accounts, this isn't too bad, but if you have a lot of accounts, it can be annoying. Hopefully some day the developers will add an Expand/Close All button to make this easier. That's why I suggest doing Print and opening in Preview may be easier.

I don't think I remembered that control-clicking on the Portfolio headers offerer an Expand/Collapse all option, so thanks for that. The problem with this Expand All is that it opens not just to the security level, but to the individual Lot level. for many users, that makes for an almost unusable mess of data. But then, strangely, Collapse All collapses the data to the security level, instead of actually collapsing all the way to the Account level. So the trick is is to open the Portfolio set to Portfolio Value, By Account, Control-Click the header to select Expand All, and Control-Click the header to select Collapse All. Or, as I said above, just Print to a PDF file/open in Preview.

You originally said you wanted a report which showed the cash in each account, and this achieves that. But you're correct that while this will let you see the Cash in each account, there's no way I can think of to show just the Cash without the other securities.