One possibility is you used the Refund Processing Service to pay your TurboTax Online fees. If you did, your TurboTax fee plus the additional processing fee (plus sales tax) is deducted from your Federal tax refund.
Another possibility is your refund was reduced by the government, either to correct an error, or through a refund offset. The IRS Where's My Refund tool will contain a disclaimer if your refund may have been offset.
You'll get an explanatory letter from the government if your refund differs from what was on your filed return.
Federal and State refunds are issued separately, so you may have gotten one but not the other.