When power companies transfer power to you the customer via the high tension lines, they bump up the voltage to several hundred thousand volts.

When power companies transfer power to you the customer via the high tension lines, they bump up the voltage to several hundred thousand volts. This is done in order to keep energy losses to a minimum. Given that Pin = Pout, and that P = IV (power = current x voltage), how does raising V lessen the loss of energy as it travels to the customer?