I am traveling to Bali, how much do I tip at Restaurants and Hotels?

I am from the States. How much should I tip and should I tip in $USD or Indonesian Rupiah?

Well, in hotels and restaurants, the tips are pretty much included as "service charge". It is usually 5% at restaurants, and that is already more than enough. But you do want to give extra to those that have been kind and hospitable enough during your stay, so here's my personal tipping tip (pardon the pun):
- waiter and waitresses: Rp10k-Rp 20k/waiter (just tip the main waiter that waits your table).
- bellhop, porters, doormen and the likes: Rp 5k-Rp 10k/person. (but if you have tons of luggages, you can consider tipping more, like Rp20k).
- concierge/front desk at hotels: Rp20k-Rp50k/person (top end hotels like Four Seasons, Ritz Carlton for examples would get the top tips).
- tour bus drivers/tour leaders: Rp10k/person. (cab drivers don't get tipped in Indonesia)

Hope the above list helps. (exchange rate varies, but on average it's about $1=Rp10,000). Tip in Rupiah, cause it's so hard to exchange usd here in Indonesia. They only accept bills larger than $10, it has to be in perfect crisp condition, and only certain serial numbers are accepted.

The tip is not mandatory in Asia, not like in U.S.
If you want to tip them, you can either use Rupiah or USD. Normally, USD 2-3 (about Rp.18,000-27,000) is enough. But, if you want give more like you tip in U.S., I believe they will not reject it and in return they will treat you really well. Anyway, always good to tip people to show our appreciation of what they have been done.

Tips are not mandatory in Bali.
But if you want to tip in restaurants, the amount is normally around 5% until 10% of your transactions, minimum is around IDR 20,000 ($ 2). USD or IDR is ok.
At the hotel, you're suggested to tip the room boy when check-in around IDR 20,000 ($2) too.