The phrase "Total Power Exchange" was coined by Steven S. Davis in the newsgroup alt.sex.bondage during his debates with Jon Jacobs in the mid 1990's. In 1997 Davis gave this definition, in bold, along with a lot of asides (in brackets):
A TPE (Total Power Exchange) relationship, sometimes described as an
absolute lifestyle D&s relationship (that such relationships can actually be neither "total" or "absolute" is agreed; these are ideal states to be worked towards but which will not be achieved, which is why TPE may be better seen as a process or goal than as a state), is a relationship in which no impediment to the exercise of the owner's power is accepted (some may, of course, exist, and what prudent owners do is to avoid direct collisions with these impediments, while working to overcome those that can be overcome, nor will a sensible owner try push a slave into things that are hard limits for her (but the owner might push a slave up against what the slave thinks are hard
limits but which she can in fact overcome)). Such things as safewords, contracts, negotiated limits, and anything else which recognizes/acknowledges/formalizes limits on the owner's power tend to be viewed as negative things in TPE
Let's take out all the italicized portions to get to the heart of the matter...
A TPE (Total Power Exchange) relationship, sometimes described as absolute lifestyle D&s, is a relationship in which no impediment to the exercise of the owner's power is accepted. Such things as safewords, contracts, negotiated limits, and anything else which recognizes/acknowledges/formalizes limits on the owner's power tend to be viewed as negative things in TPE.
Ah, that's better. Much easier to read and understand. Right?
But what does TPE actually mean? I think the term itself is somewhat misleading - all three words of it, in fact. First, as stated above, "total" is a pretty difficult thing to achieve.
Second, the dominant acquires authority, not just "power". The dominant's control of the submissive is acknowledged as being rightfully his. Finally, power or authority is not "exchanged". It is unilaterally taken by the dominant from the submissive.
At its most basic level, TPE means the dominant, whether a man or a woman, has complete control over the submissive's life, in as much as that's possible. The dominant may tell the submissive when to wake up, how to dress, where to go during the day, when to come home by, what to cook for dinner, and how to spend the evening. If the submissive, for example, doesn't like the outfit the dominant has picked out, too bad. If the submissive wants to watch American Idol but the dominant wants to see Justified, they watch Justified. The submissive completely surrenders to the wishes of the dominant.
Clear as mud now? What questions do you have? I'll do my best to answer them in the comments.