Treasury Secretary Timothy Geithner (GUYT'-nur) says a key goal of financial reform is to avoid the supersizing of banks while reining in unreasonable risk-taking.

Geithner tells ABC there is "enormous resistance" to a regulation bill pending in Congress and says "that's why it's been so hard to get this done."

The secretary said in an interview broadcast Thursday that the government must "make sure that you're limiting" how big banks can get.

Geithner said Washington must "put them out of existence, dismember them," without a taxpayer bailout "if they mess up and they take themselves to the edge of the cliff again." He said he's confident Congress will come to agreement on sweeping financial overhaul legislation.