How to filter a measure by all values

[mumair]

So currently I have DAX code as follows:

Measure = sumx(FILTER(Qty, Qty[ID #] = "53101"), [Sales])

This correctly sums up all the sales for a given ID. However, I want to do this for all sales across all IDs. How do I do this? Also, sales is a measure and not a column if that makes a difference.