Identify missing periods and years

It is probably a bit more involved than you want it to be, but you should check out this article. How to return 0 instead of BLANK in DAX - SQLBI

You can do this in Power Query too Anonymous . See code below:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("pdW9asMwEMDxVwmaRdHX6U5zmq1Dh27Bg3FMCYRQ0jxQn6VPVoeCQyLBSSc8GHv4cUh/y/u9et29f1il1e40T9fLcRpPy4MzFpfb7f3vT/21SdoivRijBn2X38bz4Xsav+YO2GqkDN6O1/lyPH/+uyRwVx+DZ8bu4iNl/OPwqUdPmJ71593s8sE7ZnG6eIzs+LdmXGszQceQyYUYm2HQEC0fY6t7911NjHI+Bj5GsZ4o1sQo9yFb+kKMYh4ha70Uo29txmtH2bIXYmyGQSMyhwsJ3NWPUBOjmKcAfIzy4VM2fClGsY+W29M+PlbFGNr/pt5nX2khxmbYa+OZw4UE7uonm9VSiFHO18Qo15OpiVHsY8SKGMU8mGV8NQx/", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [dept_Code = _t, Job_Desc = _t, Fin_Yr = _t, Qtr = _t, #"$" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"$", Currency.Type}, {"Qtr", Int64.Type}, {"Fin_Yr", Int64.Type}}),
    JobDesc = Table.Distinct(Table.SelectColumns(#"Changed Type", "Job_Desc")),
    Years = Table.Distinct(Table.SelectColumns(#"Changed Type", "Fin_Yr")),
    Qtr = Table.Distinct(Table.SelectColumns(#"Changed Type", "Qtr")),
    DeptCodes = Table.Distinct(Table.SelectColumns(#"Changed Type", "dept_Code")),
    #"Added Custom" = Table.AddColumn(DeptCodes, "Job_Desc", each JobDesc),
    #"Expanded Job_Desc" = Table.ExpandTableColumn(#"Added Custom", "Job_Desc", {"Job_Desc"}, {"Job_Desc"}),
    #"Added Custom1" = Table.AddColumn(#"Expanded Job_Desc", "Fin_Yr", each Years),
    #"Expanded Fin_Yr" = Table.ExpandTableColumn(#"Added Custom1", "Fin_Yr", {"Fin_Yr"}, {"Fin_Yr"}),
    #"Added Custom2" = Table.AddColumn(#"Expanded Fin_Yr", "Qtr", each Qtr),
    #"Expanded Qtr" = Table.ExpandTableColumn(#"Added Custom2", "Qtr", {"Qtr"}, {"Qtr"}),
    #"Added Custom3" = Table.AddColumn(#"Expanded Qtr", "$", each 0),
    #"Appended Query" = Table.Combine({#"Added Custom3", #"Changed Type"}),
    #"Grouped Rows" = Table.Group(#"Appended Query", {"dept_Code", "Job_Desc", "Fin_Yr", "Qtr"}, {{"Amount", each List.Sum([#"$"]), type number}})
in
    #"Grouped Rows"

You get this:

It does this by creating a table of all possible combinations of department, job code, year, and quarter with $0, then appends that with the original data. I then group it all to get rid of duplicate combinations and have a final total.

How to use M code provided in a blank query:
1) In Power Query, select New Source, then Blank Query
2) On the Home ribbon, select "Advanced Editor" button
3) Remove everything you see, then paste the M code I've given you in that box.
4) Press Done
5) See this article if you need help using this M code in your model.