Fully reporting your investment sales (cost basis and holding period) is the best way to let the IRS know you had a loss (or at least no gain).
Technically, you are supposed to report all your income on your tax return, which would include the gross proceeds on Form 1099-B.
If all of your investment sales were of "covered securities" (cost basis and holding period reported), then it may not make any difference. If, however, any of them did not report a cost basis, the IRS may only see your gross proceeds and treat it all as income.
the rule (explained in IRS instructions) is :
a) covered transactions without adjustments do not require Form 8949.
b) covered transactions with adjustments (i.e. wash sales) must be detailed on 8949 or your other forms in the manner of 8949.
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If you summarize a) no mailing is necessary
If you summarize b) either attach (*) or mail in the details .
(*) some users report TurboTax may prompt you to attach a PDF file of details.
Box A and Box D are your covered transactions.
a) is the only Exception to the IRS requirement to list in detail every closing transaction you make during the year.