DETROIT — Detroit’s emergency manager today filed a plan to restructure the city’s $18 billion debt by making cuts to pensions and creditors while offering a blueprint for emerging from the largest municipal bankruptcy in U.S. history.

An early draft of state-appointed Emergency Manager Kevyn Orr’s plan called for city pensioners to receive $4.3 billion in payments and bondholders about $1.1 billion during the next 40 years. That draft also detailed plans to help pensioners keep more of what they are owed by using state and private funds to protect against the sale of city-owned art at the Detroit Institute of Arts.

The plan still faces numerous obstacles. Most aspects are still being negotiated in mediation sessions with stakeholders. Court appeals are all but certain even after the final version is approved in bankruptcy court.

The early draft included the possible spinoff of the city’s Water and Sewerage Department to a regional authority. The city would receive $47 million annually under a lease deal.

Orr included in his early draft a promise of millions of dollars from foundations, the state and the Detroit Institute of Arts to prevent any possible sale of city-owned pieces in the museum to bolster at-risk pensions.

The city also would establish a voluntary employees’ beneficiary association that would provide health care benefits to retirees.