Originally Posted by sfvoyage
Yes, ATMs are your best bet. They can be found everywhere in Jakarta and Bali, and at the airports.
For US dollar bills, rates at most money changers various by denomination: the larger the bills, the better the rate. So, take a variety of $20, 50, & 100 bills to suit your needs.
Banks offer better rates than money changers, but banks (at least in Jakarta) only take clean, crisp, unfolded, unmarked, un-smudged new USD bills from specific recent years and alphabets (at the start of the serial number).
If you take USD in cash, make sure you have only bills not older than 2003. All 1996 bills and some serial numbers of 2001 are not easy to change. And be aware: 11 out of 10 "authorized moneychangers" will try to cheat you one or the other way.