But what if you do that -- and then the boss takes credit for your idea?
First, don't take any action until you've had time to think it through. Reacting in anger -- or bursting into tears -- isn't going to help the situation and will probably make it much worse. Second, take the time to think about who your boss is as a person before you craft a response.
Maybe your boss has been under increasing pressure, and she feels that she must come up with a new idea or she's going to lose her position.
Or, it could be that your boss is just a jerk.
If you feel she made the decision because she's feeling insecure about her position, or simply overwhelmed by her job, then set up a time to talk. During this discussion, have your points before you in writing so that you don't attack her, but establish the fact that it was your idea and you don't understand why she took credit.
If he or she is just being a jerk, then you need to be more careful. People who are a**hole bosses really don't care about anyone but themselves and won't hesitate to make your life miserable if you challenge them.
No matter what kind of boss you have, it's a smart idea to document your work so that it's clear you came up with the idea. Then, share the idea with your team so that it's recorded as your idea and your boss (or anyone else) can't claim complete credit. (Sometimes your boss may hone the idea a bit, and in that case, make sure you give her kudos for her input. Bosses can be as insecure as anyone else, and they may need a pat on the back.)
It's important that you get credit for your ideas, and that your career benefits from them. If your boss consistently tries to hog the limelight and won't give you credit for your contributions, you can't let that go unanswered. Either talk to her as diplomatically as possible -- or start looking for a new boss who is willing to help you achieve your potential.