Jamie Dimon apologizes

>>> on capitol hill today the man roundly considered the nation's most powerful banker, the ceo of jpmorgan chase , jamie dimon took questions from the senate banking committee about his bank's outsized trading losses disclosed last month. a lot of the back and forth focused on any institution too big to fail and persistent worries that giant wall street banks are still taking reckless risks that will somehow end up in the lap of taxpayers. nbc's kelly o'donnell was there and is with us from the hill tonight. kelly , good evening.

>> reporter: good evening, brian. any time someone from wall street is saying i'm sorry, that stirs up a lot of dread around here about the risk to taxpayers that new mistakes might trigger some future bailout. when the bank with the best reputation for managing its own risk runs in trouble, congress asked the man in charge to come here and explain. long considered the rock star of wall street , today jamie dimon , the ceo of the country's largest bank was jeered by protesters. dimon came to deliver a high-profile apology.

>> we made a mistake. i'm absolutely responsible. the buck stops with me.

>> reporter: in april jpmorgan chase launched at least $2 billion and counting of its own money using a complex strategy of trades that were meant to protect the firm's overall financial strength but did just the opposite, exposing the bank and its shareholders to steep losses.

>> something obviously went very wrong.

>> we feel terrible. but no client, customer or taxpayer money was impacted by this event.

>> reporter: dimon has been criticized for how he initially minimized the failures as a tempest in a teapot .

>> when i made that statement, i was dead wrong.

>> reporter: today dimon said he had been given bad information by his senior staff. his typical charisma and confidence unfazed today. this was not a hot seat grilling. but some democrats did get under dimon 's skin.

>> this is not your hearing. i'm asking you to respond to questions.

>> reporter: many democrats want new restrictions on commercial banks for making certain high-risk investments.

>> i think the question that bothers most people is what's to stop this from happening again.

>> we have to get rid of anything that looks like too big to fail. we have to let our institutions fail. part of the health of the system.

>> andrew sorkin from "new york times" wrote the book "too big to fail" about the financial meltdown.

>> whether things get tighter.

>> reporter: senators did not hammer dimon for details about the failed trade and how much jpmorgan has actually lost. he insists talking about those specifics could lead to more losses. following his testimony, cnbc pressed him on that point.

>> some estimates say the loss could total $5 billion.

>> i've consistently told you i'm not going to tell you. on july 13th we'll tell shareholders what it was in the quarter.

>> reporter: dimon said jpmorgan chase salaries, including his own, could be cut back when the company finishes its own investigation.

>>> kelly o'donnell from washington tonight.