If this data has not been de-identified, Ascension has violated federal law by giving it to Google.
My bet is that is has been de-identified... and this article is a bit of fear mongering...
"The data involved in Project Nightingale encompasses lab results, doctor diagnoses and hospitalization records, among other categories, and amounts to a complete health history, including patient names and dates of birth."
Not if Google is engaged as a contractor and has signed the requisite non-disclosure/confidentiality agreements.