It’s been a rough few days for JPMorgan Chase CEO Jamie Dimon. First came news that his company suffered a $2 billion trading loss. Then came reports that the loss might be closer to $3 billion. Now, Dimon is going to have to go before the Senate Banking Committee to explain what happened. The invitation comes as the committee finishes its efforts to implement Wall Street reform. Critics of the big banks say this is the perfect opportunity to do something about institutions that are “too big to fail” and argue JPMorgan Chase should be broken up.