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So now you have a pretty chart on your Account page! Excellent. The next thing your users will do is click on it to drill down... that's a thing isn't it. No. No drill down for you! At leas there is an Idea or two for that - go vote for it. And there is a seemingly related Known Issue but that is only for Lightning Home. So why a drill down on Record Page report charts is an upcoming feature and on Home Page Report Chart is a Known Issue, I don't know. It's not specifically on the Lightning Roadmap document but it must just be under "Chart parity" which is set for FutureOoh, apparently Drill Down is in Winter '18, but I have yet to try it. .
So until this is fixed, you are going to need TWO reports doing exactly the same thing. And because the main report without a Parameter for the Account is a bit useless I reckon you need two reports anyway.
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