Local government workers are to be consulted over planned changes to their pensions after "long and tough" negotiations came to an end.
Unions and the Local Government Association (LGA) will consult workers and councils across England and Wales, raising hopes that a deal involving council workers can be agreed.
Union officials said the proposals struck a "fair balance" between the conflicting interests at stake.
The Local Government Pension Scheme (LGPS) is the biggest in the UK and the fourth largest in the world, holding £145 billion in investments and assets, and has four million members.
Sir Merrick Cockell, chairman of the LGA, said: "The LGA's objective in this process has been to ensure that the LGPS continues to be sustainable into the future by developing a set of proposals that are affordable for employers and council taxpayers while being fair to members.
"Our aim in reaching agreement on these proposals was to give employers the future cost stability they need. In my view, employers can be confident that these proposals, coupled with forthcoming cost control mechanisms, meet that aim.
"Along with the LGPS unions, we shared the goal of encouraging existing members to stay within the scheme and new employees to join. These proposals are an example of us working together to achieve such shared goals."
Heather Wakefield, national officer of Unison, said: "The negotiations have been long and tough and have taken place in a demanding political and economic climate.
"The process has shown that Unison, the LGA and the other local government unions can work productively together in the best interests of LGPS members and potential members."
She said the proposed agreement promised a sustainable, defined benefit scheme, designed to protect existing members and to be affordable for the low-paid and part-time workers who are its majority, adding: "Under exacting circumstances, we have achieved the best possible outcome."
Brian Strutton, national officer of the GMB, said: "GMB members in the local government pension scheme will be relieved that at long last the uncertainty is over and they are able to see the future proposals for their pension scheme.
"Jointly negotiated by employers and unions and ratified by Government, I believe the proposals strike a fair balance between all the conflicting interests we have had to take into account.
"Most importantly, I believe the proposals lay the foundation for continued sustainability of the LGPS, which Government's original proposals would not have done.
"In reaching this deal, there have had to be compromises that will affect individuals differently. That's why, after a period of briefing and consultation, GMB will formally ballot members on this joint offer so that they can decide whether or not it is acceptable."
Peter Allenson, national officer of Unite, said: "Unite re-entered negotiations to ensure that we achieve the best outcome for LGPS members current and future within the terms of reference of the discussions.
"This has been a real negotiation between the trade unions and employers and it is right that our members should now vote on whether to accept or reject the proposals."
Other groups of workers, including doctors, teachers and civil servants, are still in dispute with the Government over its pension reforms, with industrial action planned or threatened in the coming weeks and months.