Is it acceptable for university to ask for detailed financial report? I'm applying for a university in the USA and one of the section requires to enter up to five previous employees, their contacts, start/end dates, hours per week, and salary. I mean, that some of the previous aspects are considered personal in Europe.

Is it acceptable for university to ask for financial data and should one provide full, candid answers?
I'd say those details are a bit too detailed for comfort, especially for a graduate admission programme. However, the technical rationale behind could be that they might have some consideration for scholarships based on the financial details you provide. In the end, it is your decision. 

If you are still concerned about the necessity of those details, you may request the respective department of the University for a clarification of the reason behind them.