Let's assume that the cost of an employee's health insurance is $300 per pay period and that the employee is responsible for paying 25% of that cost through payroll withholding. One way to handle the withholding is to credit Health Insurance Expense for the $75 (25% of $300) withheld from the employee. The company will then debit Health Insurance Expense for the full insurance billing of $300. This will result in $225 being reported as the company's health insurance expense for that pay period.
An alternative would be to credit a liability (e.g., Employee Withholdings for Insurance) for the $75 withheld from the employee. When the company pays the insurance bill of $300, it will debit the liability account for $75.
Under either method, the company's expense is $225 per pay period.