Buffett challenges Murdoch on tax returns

NEW YORK (CNNMoney) -- Warren Buffett has a message for Rupert Murdoch and the Wall Street Journal: Sure, I'll release my tax returns, if you do too.

Last week, the Wall Street Journal published an editorial that asked Buffett to disclose his tax returns. The piece, "Mr. Buffett's Tax Secrets," took issue with Buffett's plan to hike taxes on some of the super-rich.

The Journal's conservative editorial board doesn't think that's a great idea, saying that Buffett should instead "educate the public" by letting "everyone else in on his secrets of tax avoidance by releasing his tax returns."

Asked about the editorial on Tuesday at Fortune's Most Powerful Women Summit, Buffett said he was willing to release his tax returns, on one condition:

"I think it might be a terrific idea if they would just ask their boss, Rupert Murdoch, and he and I will meet at Fortune, and we'll both give you our tax returns and you can publish them," Buffett said.

"I'm ready tomorrow morning," he added. (Read full transcript of interview)

Representatives from News Corp. (NWSA, Fortune 500), the parent company of the Wall Street Journal, did not immediately respond to requests for comment.

Buffett has become a political lightning rod in recent weeks after the Berkshire Hathaway (BRKA, Fortune 500) chairman let the White House attach his name to a tax proposal.

The "Buffett Rule" is a guideline -- that Buffett himself came up with -- designed to ensure that those making more than $1 million do not pay a lower overall tax rate than those who earn substantially less money.

For most people, wages make up a majority of their income, so when they get a raise their average tax rate may go up.

But millionaires -- and in Buffett's case, billionaires -- typically have several sources of income, some of which are taxed at lower rates, if at all.

As a result, Buffett says he enjoys a lower tax rate than his secretary. Correcting that discrepancy is the aim of the Buffett Rule.

Buffett's words twisted on taxes

And that secretary? The Journal wants to see her return as well.

"We wouldn't want to violate their individual privacy, but since Mr. Buffett is using [his employees] to make a political point, perhaps he'd be willing to disclose the most important lines on their returns without disclosing their names," the op-ed said.

Buffett didn't go quite that far, making no requests to see the tax returns of Murdoch staffers.

Buffett says he paid $6,938,744 in federal taxes last year -- only 17.4% of his taxable income.

Meanwhile, Murdoch was given a substantial raise recently, despite the hacking scandals that rocked his media empire. His total compensation jumped 47% to $33.3 million in the latest fiscal year, according to regulatory report News Corp. released in September.

--Fortune's Carol Loomis moderated Tuesday's discussion with Buffett at the magazine's Most Powerful Women Summit. She is a longtime friend of Buffett's and the editor of his "chairman's letter" in the Berkshire annual report.