Many of the muggers are young kids in Rio, so watch out for that. When I was there, my iPhone generally stayed in my hotel room safe. I generally left the hotel with my passport card (not the passport book), one credit card, and enough cash for a taxi back to the hotel from almost anywhere in town.

I noticed small groups of people just hanging around outside of ATMs and banks, so please exercise caution in those locations too. The hotels seemed to have ATMs on the premises, so this would be safer but possibly at the expense of high fees.