Trading losses caused some headaches during the financial crisis, but it was bad mortgage lending that really hurt big banks like Bank of America (BAC 2.03%). While some argue separating investment banking operations and commercial banking activities would solve all of the financial problems, the actually picture may be a bit murkier.In this segment of The Motley Fool's financials-focused show, Where the Money Is, banking analysts Matt Koppenheffer and David Hanson discuss the Volcker rule, Glass-Steagall, and Bank of America.