If I give my two weeks written notice does the company have to pay me for the entire 2 weeks if I am willing to work the entire 2-week duration?
Colorado follows the legal doctrine of "employment-at-will" which provides that in the absence of a contract to the contrary, neither an employer nor an employee is required to give notice or advance notice of termination or resignation. Additionally, neither an employer nor an employee is required to give a reason for the separation from employment. In Continental Airlines Inc. v. Keenan (1987), the Colorado Supreme Court recognized at-will employment in Colorado, and noted that there may be certain exceptions to the presumption of at-will employment.
The general principle behind the concept of employment-at-will is that the doctrine promotes efficiency and flexibility in the employment context. Employment-at-will allows employees to seek out the position best suited for their talents and allows employers to seek out the best employees for their needs.
There are no federal or state laws requiring employees to provide their boss with two weeks notice when quitting.
There are no federal or state laws requiring employers to allow an employee to stay on once the employee has given her/his two weeks notice when quitting.
No, in fact an employer could say to you, "Sorry there's no need to stay another two weeks. You are free to leave right now. Goodbye."
Can they just say that the day I give my notice that that is my last day and only pay me for that day?
Yes, but you might not get a day, or even 30 minutes of paid time.
Some people will quit ONLY after they have secured their next job.
An employer could say, okay, we wish you well. But, we don't need you for two more weeks. We'll pay you for an hour, but you must leave now.
Good luck.