Create Table with all the possible group combinations

By using great code from this post  by AlexisOlson , this is one solution that should be reworked, tweaked and turned into a function.

1st requirement

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUfLzdPYHUsamSrE60UpGCBEjAwOwkDFCyAQqZIIQ0jUFCsUCAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"DOC ID" = _t, #"Customer ID" = _t, Value = _t]),
    Type = Table.TransformColumnTypes(Source,{{"DOC ID", Int64.Type}, {"Customer ID", type text}, {"Value", Int64.Type}}),
    L=Type[DOC ID],
    L2= Type[Value],
    N = List.Count(L),
    Subsets = 
        List.Transform(
            {0..Number.Power(2, N)-1},
            (i) => List.Transform(
                        {0..N-1},
                        (j) => if Number.Mod(Number.IntegerDivide(i, Number.Power(2, j)), 2) = 1
                                then L{j}
                                else null
                    )
        ),
    Custom1 = List.Select(List.Transform(Subsets, each let l=List.RemoveNulls(_), t= List.Transform(l, Text.From)  in Text.Combine(t)), each _ <> ""),
    Subsets2 =
        List.Transform(
            {0..Number.Power(2, N)-1},
            (i) => List.Transform(
                        {0..N-1},
                        (j) => if Number.Mod(Number.IntegerDivide(i, Number.Power(2, j)), 2) = 1
                                then L2{j}
                                else null
                    )
        ),
    Custom2 = List.RemoveNulls ( List.Transform(Subsets2, each let l=List.RemoveNulls(_) in List.Sum(l))),
    ID = List.Repeat({Type[Customer ID]{0}}, List.Count(Custom2)),
    Table = Table.FromColumns ( {ID, Custom1, Custom2}, {"Customer ID", "Unique ID Combinations", "SUM Value"}),
    #"Changed Type" = Table.TransformColumnTypes(Table,{{"Unique ID Combinations", Int64.Type}, {"SUM Value", type number}}),
    #"Sorted Rows" = Table.Sort(#"Changed Type",{{"Unique ID Combinations", Order.Ascending}})
in
    #"Sorted Rows"

2nd requirement 

I referenced the table above in the Source step

let
    Source = Table,
    Type = Table.TransformColumnTypes(Source,{{"Unique ID Combinations", type text}}),
    RemovedSum = Table.RemoveColumns(Type,{"SUM Value"}),
    InsertedDOCID = Table.AddColumn(RemovedSum, "DOC ID", each Text.ToList([Unique ID Combinations])),
    ExpandedDOCID = Table.ExpandListColumn(InsertedDOCID, "DOC ID")
in
    ExpandedDOCID