US pension funds are still heavily invested in equities - close to 50% of assets. In fact US pensions have the highest concentration of equities among all OECD nations.
But no worries. Corporations are shifting to defined contributions plans, letting their employees take this equity risk. And for the remaining defined benefits plans, the pension managers will use corporate bonds to discount pension liabilities - the wider the spread, the lower the "present value" of what they owe to future retirees.
Good luck with your retirement plans.