The long-awaited final details of the Securities and Exchange Commission’s plan to mandate the use of interactive data are finally poised to become public.

More than six months after it first published its proposed rule to phase-in the adoption of XBRL, or extensible business reporting language, which would require companies to furnish tagged data with their financial reports, the SEC will vote on whether to adopt the amendments at an open meeting slated for Dec. 17.

As originally proposed, the 500 largest public companies in the United States would begin including XBRL-tagged statements with their financial reports starting next spring, followed by other large accelerated filers in 2010, and all other registrants in 2011.

The rule proposal floated in May would provide for 30-day grace periods for a company’s first XBRL filing and its first filing with detailed tagging of footnotes, which would be required in the company’s second year of compliance with the final rule. To the relief of many, the rule proposal doesn’t require auditor attestation.

The XBRL rule has been a top priority for SEC chairman Christopher Cox, who has promoted the technology tirelessly throughout his tenure at the commission. In addition to touting the benefits of interactive data for investors, Cox oversaw the expansion of the SEC’s voluntary XBRL filing program and the release of free XBRL reader programs on the SEC Website in an effort to prod development of other XBRL applications.

The SEC is also scheduled to vote next week on amendments to require mutual fund risk/return summary information to be filed with the Commission in XBRL and amendments to permit investment companies to submit portfolio holdings information under the SEC’s voluntary XBRL filing program without being required to submit other financial information.

Other items on the open meeting agenda include a vote on the Public Company Accounting Oversight Board’s 2009 budget and related annual accounting support fee; a vote on amendments that would define terms related to annuity contracts under the Securities Act of 1933; and a vote on amendments related to periodic reporting requirements under the Securities Exchange Act of 1934.