Verizon Wireless said Friday it has completed its US$5.9 billion purchase of Little Rock, Ark.-based Alltel, making Verizon the nation’s largest mobile phone company. Verizon said Friday it will also take on $22.2 billion in Alltel debt. Basking Ridge, N.J.-based Verizon says it will retain all Alltel employees below the executive level as the company assesses which positions need to be cut or kept.