It also reduces expenses for union-sponsored programs and diverts employee bonuses to cover retiree healthcare benefits.

It also will divert employee bonuses to cover retiree health care costs, and reduce expenses for union-sponsored programs.

The UAW has suggested using the money to cover retiree health care obligations, freeing up more industry resources for operational needs.

Among the employers that still cover retirees, a growing number are shifting retirees into insurance exchanges.

Warren said that stagnant wages have contributed to Social Security benefits that are too low to cover retirees' living expenses.