There's one thing everyone can agree on about the financial overhaul agreement lawmakers reached early Friday: There's a lot they don't know yet.

The roughly 2,000 page bill intended to rein in risk on Wall Street and protect consumers contains nearly 400 items where regulators from various federal agencies must fill in the rules about how the law will be implemented.

Among the numerous details still to be ironed out: how mortgages will be overseen by the new Consumer Financial Protection Bureau and how the Securities and Exchange Commission will oversee credit rating agencies.

The lack of hard-and-fast specifics may be one reason investors had a muted response to the bill: the major Wall Street indexes barely budged Friday, and bank and insurance stocks mostly rose on the day.

"We will be able to conduct a fuller assessment of its impact after the regulators issue new rules," Citigroup CEO Vikram Pandit said in a statement. Similar comments came from other big banks.

It's common for Congress to pass legislation and then leave the details to regulators, said J.W. Verret, a scholar at the Mercatus Center at George Mason University who frequently consults with legislators and agencies on financial regulation. But with this bill, "open-ended authorizing legislation was passed at a more rapid rate than we've ever seen before."

Steven Adamske, a spokesman for the Senate Banking Committee, defended the process. "Legislation is about broad policy," he said. Laws that get too specific can tie the hands of regulators in the future, he said, so Congress leaves the details up to the experts. "The intent of the legislation is actually pretty clear."

Typically, legislation will set a date for rules to be in place so the law can take effect. The process once a law is signed by the president typically involves agencies writing a proposed set of rules; they ask for public comment and then set final rules. At least some of the financial regulatory provisions have specific dates for the rules to be set.

The credit card law passed in May 2009, for instance, left nine months for regulators to write the rules. It may take several years before all elements of the financial reform bill are in place.

With the ink barely dry on the financial reform bill, it's not yet clear how much wiggle room there is in various aspects of the agreement. But lobbyists from all sides can be expected to weigh in to try to sway regulators.

"Some things may sound like a good idea, but may have a consequence that wasn't intended," said John Hall, a spokesman for the American Bankers Association.