Domestic bank-to-bank transfers within the United States are usually available the next business day. Transfers within the same bank will be faster and may be processed immediately. This is because the funds are staying within the same financial organization.
If you deposit cash, that money goes directly to your account and will be ready for you to use immediately. But for checks and other items that might need verification (to protect you and the bank), the money usually won't be available until the next business day.