Hi Deepan,
If you are looking for an access right that will give you the ability to approve all the ideas in the PPM environment, except the ones that you created, then I would say that there is not such rights like that in PPM.
Like Shailey mentioned the Idea - Approve - All rights will make sure that the resource is able to approve any idea in the system, regardless the "created by" field.
And you cannot depend on the Idea - Approve instance specific right either, as that will take a manual intervention to select all ideas and then de-select the ones that the respective user has created. Even after doing that, you have add other ideas, that will be created in the future by any other user. So this is not a feasible thing to do.
To conclude, there is no such right that will give an user Idea approval rights, for all the ideas except the ones created by the user himself/herself. Hope that answers your question.
Cheers!