Is 15 mio IDR as Salary OK for a couple in Jakarta !

Yes I am sure it will be. You just have to be careful and learn along the way.

Love your avatar and good luck with your new job and new life in "The Big Durian."

15 million will do it, more so if you have the apartment free, gratis and for nothing.
I spend about 1.5 million on supermarket shopping, about 2 million on various bills, including school fees, and not that much more.
The whole lot comes to 5 or 6 million, including eating out whenever we feel like it.
We don't booze, and don't go to top end restaurants - the cheaper ones are commonly better.

Guys thank you thank you so much. I really appreciate it.

Hoping to meet along with you guys one day :-) Wink wink.

Have a great day !!!

I believe its definately enough according to the lifestyle you describe. But if you go out more than a few times a week you will struggle to save.

But as long as you learn the surroundings and understand Jakarta lifestyle you will adapt. 

Goodluck, hope you enjoy Jakarta.

will be quite difficult to save, transportation and dining out is mostly where you'll burn. I spent Rp 3 mio on gas, dining out around Rp 300k to Rp 500k for two. but if you dont go out as much, you'll be ok I guess.