Is doing Wudu with a soap; Bid'ah?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

There is a disagreement among the scholars regarding the ruling on performing ablution while using soap. But the majority of scholars are of the opinion that soapy water cannot be used for ablution or Ghusl (ritual bath). When soap gets mixed with water, it makes it inappropriate for ablution, because soap is among the things that are not habitually found in water.
But the Hanafi School of jurisprudence as well as Ibn Taymiyyah are of the opinion that water is good for ablution as long as it is called water and is mixed with something that cannot be removed from it or that it cannot be removed except with difficulty. Allah Says (what means): {O you who have believed, do not approach prayer while you are intoxicated until you know what you are saying or in a state of janabah, except those passing through [a place of prayer], until you have washed [your whole body]. And if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women [i.e. had sexual intercourse] and find no water, then seek clean earth and wipe over your faces and your hands [with it]. Indeed, Allah is ever Pardoning and Forgiving.} [Quran 4: 43]

Allah did not define the kind of water. So, it becomes general and means everything that is called water and there is no difference in this between one water and another water.

Allah knows best.