. on december 15 , 2017 , we filed a shelf registration statement on form s-3 with the sec to give us the ability to sell up to $ 3 billion in debt securities in amounts to be determined at the time of an offering . any such offering , if it does occur , may happen in one or more transactions . the specific terms of any securities to be sold will be described in supplemental filings with the sec . the registration statement will expire in 2020