A couple of generations ago, my Irish-American aunt married into a family of Chaldeans from Syria. The Chaldean family had been in Detroit for a couple of generations. They were all Roman Catholic.
The vast majority of them are still Roman Catholics......
As a side note, the Chaldean owner of my Marathon gas station constantly hosts car washings from his church and the local schools throughout the summer........
In talking with one of his sons recently, I suspect they are Syrian rather than Iraqis since they were extremely concerned with what has been going on in that country......