A computer-implemented method for use with a wireless telecommunications network, the method comprising: receiving a first call detail record, CDR (115; 116; 117), associated with a wireless transmission of data to or from a first electronic device (105a to 105n) of a user, determining a first target billing system (125a; 125b; 125c) associated with the received first CDR, transmitting the received first CDR to the determined first target billing system; receiving a second CDR associated with a wireless transmission of data to or from a second electronic device associated with the user; determining a second target billing system associated with the received second CDR; and transmitting the received second CDR to the determined second target billing system, thereby permitting split billing for the user across multiple billing systems, wherein the received first CDR comprises: a first identifier corresponding to the first electronic device; a second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the first electronic device; wherein the determination of the first target billing system is based on at least the first identifier corresponding to the first electronic device, the second identifier corresponding to the user, and the third identifier corresponding to the route by which the data was transmitted to or from the first electronic device; wherein the received second CDR comprises: a first identifier corresponding to the second electronic device; the second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the second electronic device; wherein the determination of the second target billing system is based on at least the first identifier corresponding to the second electronic device, the second identifier corresponding to the user, and the third identifier corresponding to the route by which the data was transmitted to or from the second electronic device. receiving a first call detail record, CDR (115; 116; 117), associated with a wireless transmission of data to or from a first electronic device (105a to 105n) of a user, determining a first target billing system (125a; 125b; 125c) associated with the received first CDR, transmitting the received first CDR to the determined first target billing system; receiving a second CDR associated with a wireless transmission of data to or from a second electronic device associated with the user; determining a second target billing system associated with the received second CDR; and transmitting the received second CDR to the determined second target billing system, thereby permitting split billing for the user across multiple billing systems, wherein the received first CDR comprises: a first identifier corresponding to the first electronic device; a second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the first electronic device; a first identifier corresponding to the first electronic device; a second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the first electronic device; wherein the determination of the first target billing system is based on at least the first identifier corresponding to the first electronic device, the second identifier corresponding to the user, and the third identifier corresponding to the route by which the data was transmitted to or from the first electronic device; wherein the received second CDR comprises: a first identifier corresponding to the second electronic device; the second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the second electronic device; a first identifier corresponding to the second electronic device; the second identifier corresponding to the user; and a third identifier corresponding to a route by which the data was transmitted to or from the second electronic device; wherein the determination of the second target billing system is based on at least the first identifier corresponding to the second electronic device, the second identifier corresponding to the user, and the third identifier corresponding to the route by which the data was transmitted to or from the second electronic device.