a 100 times this! Please don't have a top down mandate to have synchronised 2 weeks sprints across the organisation, just because you read that somewhere. Understand what each teams needs, and empower them to make the right decision.
Someone mentioned me in a comment where they are debating whether or not the top 10 Fortune 500 companies use Agile (as in, some methodology based on the Agile Manifesto).
My thoughts on this: worry about being nimble, not about Agile (TM). That's what the best orgs do, anyway.