I actually interviewed for two different jobs at Discover - Card side was extremely detailed and organized. Network side was much more on-the-fly and fewer layers. Network process started with a phone call from the recruiter in which she detailed the position to me, followed by a phone interview with the hiring manager, then phone interview with the person I would be replacing, and finished with a 2-3 hour in-person interview with 4 people - hiring manager, hiring manager's boss, another colleague, and the HR recruiter.
Interview process wasn't difficult, although the HR recruiter was a bit off-putting - pretty aggressive and asking extremely rudimentary questions. They also forgot to tell me to bring work samples, but after a month of silence, I was offered the position. I almost didn't accept but I'm glad I did - it seems like a really great place to work.