Quoted from ForceFlow:No, that is incorrect. The moment you create it, you own the copyright to it--it's automatic. You do not need to do anything in order to claim copyright. However, if you enter a infringement suit, you would need to register the work as a matter of establishing public record. Registering 3 months after creation grants you certain additional rights for recouping legal fees, losses, and damages if your work is part of an infringement suit. Registering also allows you to ban the import of infringing content through US customs. There are some perks to copyright registrations, but it is not required for protection against infringement.
For anything created or published, the copyright length is the author's life plus 70 years for anything created after 1978. Or, for published works, 95 years from the date of publishing, or 120 years from the date of creation--whichever is shorter. Anything created/published before 1978 has its own set of rules.
http://copyright.gov/help/faq/faq-general.html#protect
http://copyright.gov/circs/circ1.pdf
You need to file for a patent or trademark in order to reap the benifits of legal protections for a patent or trademark.
I was in the music industry for a bit of time and what you wrote is my understanding of the law as it pertains to songwriting. I assume it would be the same for documents that are written as well.