Relatively casual, they really want to know why you are interested in the company and what you know about them. I'd say half the time was allocated just to asking the interviewers questions.
I applied online. I interviewed at Deloitte (Seattle, WA)
Interview
Preliminary informational interview with the recruiter. Invitation to interview for about an hour. The purpose is mostly to get to know you. I got asked no more than 4-5 behavioral questions.
I applied through a recruiter. I interviewed at Deloitte (Detroit, MI)
Interview
First you do phone interview with recuiter then you interview with 1 manager in audit and another in tax. The interviewers made me feel comfortable. The recuiters are the best because they guide you through every step of the way. Their response time was quick as well.
Interview questions [1]
Question 1
Why Accounting? Why Deloitte? They asked about about my resume too especially past expeirences. Some behavioral questions but they weren't hard