AT&T said it would be taking a $10 billion charge, but that the move would not have an effect on its operating profits.
The firm said Friday afternoon that it expects to record a noncash, pre-tax loss of about $7.9 billion related to actuarial gains and losses on pension and post-employment benefit plans.
Additionally AT&T said its operating results would include a $2.1 billion noncash charge for "the abandonment in place of certain network assets."
"During the fourth quarter, we performed an analysis of our network assets and determined that specific copper assets will not be necessary to support future network activity, due to declining customer demand for our legacy voice and data products and the migration of our networks to next generation technology," the company's filing said.
AT&T said neither of the charges will affect segment operating results or margins.
The company's stock fell less than 1 percent in after-hours trading on Friday.