Most bleach isn’t chlorine-based anymore, which would be the problem. Still, I would never use it in anything I drink out of. It’s not easy to completely rinse it out.
For TCA, you really don’t need to overthink it. A few rinses with hot water as John suggested have always worked just fine for me. You could include a little dish soap on the first fill if you really want to be thorough.
I would break the decanter into many pieces and bury them in different parts of the country. Make sure they’re in at least 10 different places and no less than 6 feet deep, or they may rise up, reassemble, and contaminate every wine you drink for the rest of your life.
I do think it’s really funny that some people go to such extreme measures for something that isn’t a big deal at all. I can’t imagine doing some of those things to a decanter.
I don’t think bleach should be a problem, should it? Chlorine seems to evaporate quite completely in a relatively short time, particularly when diluted.
I don’t see any need for chlorine bleach here, though, because there’s no need to sterilize or remove stains.
Break out the Chuppah. One at a time, cover the decanter and stemware with a classy piece of linen. Get some serious air. Ditch the Keds for Army Boots. Mazel Tov!