NEW YORK (CNN/Money) – In the first solo news conference of his second term, President Bush on Wednesday said he's "open to good ideas" from lawmakers about Social Security reform.

But he reiterated that any proposal must create individual investment accounts and must not include an increase in payroll taxes. He didn't specify whether that would also preclude increasing or eliminating the cap on wages subject to Social Security payroll tax. Currently, the cap is set at the first $90,000 of wages.

He also said any solution must make the system "permanently solvent." But, he noted, "I fully understand that (individual investment) accounts is not the only thing that will be necessary to make sure the system is permanently secure."

The president's comments come after a week when key Republicans publicly voiced concerns about several issues related to the president's ideas, including diverting a portion of payroll taxes to fund the accounts and funding the $1 trillion to $2 trillion estimated transition costs of creating such accounts.

"I'm certainly not going to support diverting $2 trillion from Social Security into creating personal savings accounts," said Sen. Olympia Snowe on CNN's "Inside Politics" Sunday. Snowe is a moderate Republican from Maine who sits on the Senate Finance Committee.

When a reporter asked the president Wednesday whether he would support borrowing money to fund the transition costs, Bush replied, "You're asking me to talk about specific proposals. ... I fully understand some people are concerned about whether or not this is affordable. And at the appropriate time, we'll address that aspect of reform."

That may or may not indicate a change in the president's strategy. Last December, White House spokesman Scott McClellan said additional borrowing is "what you're looking at doing as part of the transition to a better Social Security system.''

Meanwhile, last week, at a forum sponsored by the National Journal, the chairman of the House Ways and Means Committee -- Rep. Bill Thomas (R-Calif.) – commended the president for taking on the third rail of politics. But he suggested Social Security reform be combined with tax reform, issues the White House have been treating separately.

Thomas also suggested lawmakers consider solutions that go beyond any ideas expressed to date. Notably, consider funding Social Security by something other than the payroll tax. "There are other ways to deal with the issue that are smarter, both in terms of maintaining competitiveness for our business structure both at home and abroad, and that raise revenue in ways that are not as ... depressing in terms of job availability as the payroll tax," he said.

Asked what he would say to some Republicans' concerns about his proposals, the president said, "(W)hat you're hearing a little bit is ... whether or not it is worth the political price. I think it is. And I'm looking forward to leading the Congress. And I'm looking forward to taking the case to the American people."

Bush said he will reveal in more detail his legislative agenda at his State of the Union speech Feb. 2.