The Congressional Budget Office (CBO) and the staff of the Joint Committee on Taxation (JCT) updated their estimates to indicate that, by itself, repealing the mandate would reduce federal deficits by about $338 billion over the 2018–2027 period and increase the number of uninsured individuals by 4 million in 2019 and 13 million in 2027.
The report can be obtained at https://www.cbo.gov/system/files/115th-congress-2017-2018/reports/53300-individualmandate.pdf.