Big banks like Citigroup and Morgan Stanley, which were battered by the 2008 financial crisis, are once again on solid ground. But a slew of documents, e-mail messages and minutes of crucial regulatory meetings released recently by the Financial Crisis Inquiry Commission provide fresh detail about just how close to the brink both firms came. This week the commission will release another set of documents on its Web site, including an interactive timeline that goes back to the Great Depression. The site will also feature hours of previously unreleased audio recordings of interviews with major players in the crisis, like Joseph Cassano of the American International Group, who was at the center of the credit-default swaps business.