"This ruling also assures legally married same-sex couples that they can move freely throughout the country knowing that their federal filing status will not change,"  Lew said.

In its announcement, Centers for Medicare & Medicaid Services Administrator Marilyn Tavenner said: "Today, Medicare is ensuring that all beneficiaries will have equal access to coverage in a nursing home where their spouse lives, regardless of their sexual orientation."

"Prior to this, a beneficiary in a same-sex marriage enrolled in a Medicare Advantage plan did not have equal access to such coverage and, as a result, could have faced time away from his or her spouse or higher costs because of the way that marriage was defined for this purpose."

HHS Secretary Kathleen Sebelius said the department "is working swiftly to implement the Supreme Court's decision and maximize federal recognition of same-sex spouses in HHS programs."  

Sebelius described Thursday's announcement as "the first of many steps." Several groups, including the American Benefits Council, have urged the federal government to help clarify benefits post-DOMA.

The HHS announcement specifically clarifies that the guarantee of coverage applies equally to couples who are in a legally recognized same-sex marriage, regardless of where they live.

DOMA, of course, is a federal law, and only 12 states now recognize same-sex marriages. The Supreme Court decision last month struck down only one section, which stated that marriage is between a man and a woman.

Experts in health and benefits pointed out then that more guidance would be necessary to clarify and determine what will happen to same-sex couples who live and work in the 38 states that do not extend the same recognition.

Photo: Medicaid head Marilyn Tavenner, left, and HHS chief Kathleen Sebelius.

While Thursday's announcements begin to do just that, a recent poll by The ERISA Industry Committee of its members found that many organizations are in dire need of more guidance.

"The big issue, one that dwarfs almost all others, is what to do in states that do not recognize same-sex marriage," ERIC President and CEO Scott Macey said. "Our members really need to know what the rules will be before they can fully implement any new benefits strategy, especially those with calendar-year plans who will soon be in high gear for enrolling members for next year."

When asked the question, "Will you consider same-sex spouses to be married if they live in a state that does not recognize same-sex marriages?" 74 percent said they are undecided or waiting for government guidance.

Fifteen percent said they would recognize all same-sex marriages and 11 percent said they would only recognize same-sex marriages if the couple lives in a state that performs or recognizes same-sex marriages.

The poll, which was conducted from Aug. 20-27, also asked whether ERIC members planned to make changes to benefits offered to domestic partners and partners who have entered into civil unions because of the DOMA decision.

Twenty-nine percent of respondents said they plan to change the benefits offered to same-sex domestic partners and 5 percent said they would do the same for opposite-sex domestic partners. Forty-five percent said they wouldn't make changes to the benefits coverage of same-sex domestic partners and 72 percent said they wouldn't change benefits coverage for opposite-sex domestic partners.

Out of those polled, 87 percent said they offer benefits to same-sex domestic partners and 55 percent offer benefits for opposite-sex domestic partners.

When asked whether they offer benefits to same-sex partners who entered into a civil union, 79 percent said they did and 21 percent said they did not.

The majority of respondents, 59 percent, said they were not planning to change their coverage of members of civil unions as a result of the rule changes regarding same-sex spouses; 33 percent were undecided and 6 percent said they would make changes.

When asked if they require proof of marriage before providing benefits to spouses, 35 percent said no for both same-sex and opposite-sex spouses, 38 percent said they do for same-sex marriage and 58 percent said they require it for opposite-sex marriage.

The ERISA Industry Committee is a non-profit association that represents the advancement of employee retirement, health and compensation plans at America's largest employers.