In a photo from Tuesday, Dec. 10, 2013 at the Detroit Institute of Arts in Detroit, the Detroit Industry Murals by the Diego Rivera are seen in Rivera Court at the DIA. Bankrupt Detroit’s ability to retain or protect art masterpieces bought with taxpayer dollars during better times could come down to the generosity of strangers. New York auction house Christie’s is expected this week to hand over its final report on the value of about 3,200 city-owned pieces at the Detroit Institute of Arts to state-appointed emergency manager Kevyn Orr. (Carlos Osorio/AP)

A group of national and local philanthropic foundations have pledged $330 million to bolster Detroit’s municipal pension funds and help protect the Detroit Institute of Art’s collection from a sale to creditors, according to federal mediators involved with bankruptcy proceedings.

The Ford Foundation, the John S. and James L. Knight Foundation and seven other philanthropic organizations have offered millions to ameliorate two primary and seemingly unrelated concerns — the plight of pension recipients and preservation of fine art — that have dogged Detroit since it filed for bankruptcy in July.

Chief U.S. District Judge Gerald Rosen, who is overseeing the mediation, called the pledges an “extraordinary and unprecedented effort” and noted that additional foundations are expected to offer support. But the announcement did not say that an agreement has been reached with Detroit’s emergency manager, Kevyn D. Orr, who has previously called for the museum to be monetized to lessen debt obligations.

In July, Detroit filed for bankruptcy, claiming that it could not repay $18 billion in debt. The city owns the DIA’s 65,000-piece collection, which some have argued should be sold to pay creditors. According to an independent appraisal by the New York-based auction house Christie’s, the portion of the collection purchased with city funds is worth between $454 million and $867 million. Other independent appraisals have valued the collection at between $1 billion and $2 billion.

In a statement, the foundation working group announced that it hopes to move toward a “renewed and stronger” Detroit by focusing on “commitments to its retirees and preserving an extraordinary community cultural asset, the Detroit Institute of Arts.” Support also includes commitments from individuals, including a $5 million gift from A. Paul Schaap and 130 other contributions.