WASHINGTON (AP) — The top Republican on the Senate Banking Committee unveiled legislation Tuesday that would ease regulatory requirements on mid-size banks and give lenders the option for greater freedom from mortgage lending rules.

The legislation by Alabama Sen. Richard Shelby would be the most ambitious rewrite of rules governing the financial services sector since Democrats passed the groundbreaking Dodd-Frank law when controlling Congress in 2010.

The bill would lift the asset threshold for banks considered "too big to fail" from $50 billion to $500 billion, giving regulators flexibility to exempt them from tougher capital requirements and stricter oversight. It would also give mortgage lenders flexibility to avoid lending standards put in place after the 2008 financial crisis — so long as they hold onto riskier loans rather than selling them.

The bill would also give lawmakers greater oversight powers over the Federal Reserve and force changes to the way it produces a key report on its monetary policy moves, while requiring it to be submitted to Congress each quarter instead of twice a year.

The measure, labeled a "discussion draft" that's open to revision before a Banking Committee vote next week, faces a long road before becoming law. It avoids some of the biggest issues involving the 2010 law, such as trading in complex instruments known as derivatives and the powers of the Consumer Financial Protection Bureau, but still goes too far for Democratic defenders of Dodd-Frank, named after former Sen. Christopher Dodd, D-Conn., and Rep. Barney Frank, D-Mass.

Sen. Sherrod Brown of Ohio, the top Democrat on the Banking panel, called Shelby's bill "a sprawling industry wish list of Dodd-Frank rollbacks" and said that regulatory relief should be limited to credit unions and smaller community banks.

The Dodd-Frank law arose from the rubble of the financial crisis of 2008, sparked largely by the housing bubble and lax mortgage lending standards. Shelby's measure would award banks a "safe harbor" from federal mortgage underwriting standards to allow them to issue more loans to borrowers who may not be able to prove their ability to repay the loan.

The measure also would give banks with assets of more than $50 billion a chance at avoiding the strict capital standards and tighter supervision of Dodd-Frank that are aimed at preventing the collapse of institutions so big that their failure could bring down the economy. The new cap for such institutions would be $500 billion; regulators would decide whether smaller ones should meet the tougher standards.

As for the Fed, the measure would award authorship of its monetary policy report to the larger Federal Open Market Committee instead of the seven-member board of governors. It also demands more details about how the Fed determines policy and would allow board members to hire their own staff, which is aimed at giving them more independence from the Fed chair, who has a very strong hand in shaping policy.