"CynthiaMcfadden" news and stories

Martha Stewart says her five-month prison sentence cost her $1 billion.

Speaking with "Nightline," Stewart says the "legal mess" was devastating to her personal worth.

"Oh, it's inestimable -- probably more than a billion dollars, of course, and if you add in what the company was worth, absolutely," Stewart says. "And I'm a major shareholder in the company. When you are prosecuted in such a way and a great portion of wealth is dissipated, all I could think so much is 'What I could have done with all of that for the good of mankind?'"

"Nightline" followed Stewart for a day in a news piece that aired Thursday. In it, Stewart dishes on Rachael Ray as well as her 2004 legal troubles.

"I knew we had a really good thing going, and I really knew that I was not guilty of anything that could possibly harm my company," Stewart tells Cynthia McFadden. "I was pissed, OK? Pissed that something could actually affect that. The company had nothing to do with anything, but yet because I am the face and the brand -- my person -- it certainly had a harmful effect."

She says she's put that period of her life behind her.

"How can I kick myself?" she says. "There are other people to be kicked. Enough. Let's get on with the future."