CHICAGO — Federal prosecutors on Friday for the first time provided details of sexual abuse allegations against J. Dennis Hastert, the former speaker of the House, asserting that he molested at least four boys, as young as 14, when he worked as a high school wrestling coach decades ago. Mr. Hastert, 74, is not charged with the incidents of abuse because of statutes of limitation, prosecutors said, but he was accused last year of illegally structuring bank withdrawals for money he was paying to one of his victims in an effort to hide the abuse. He pleaded guilty in October...