April 3, 2020

Fabian Souza
Senior Vice President and Corporate Controller
EXELON CORP
10 South Dearborn Street
P.O. Box 805379
Chicago, Illinois 60680-5379

       Re: EXELON CORP
           Form 10-K for the Fiscal Year Ended December 31, 2019
           Filed February 11, 2020
           Response dated March 19, 2020
           File No. 001-16169

Dear Mr. Souza:

       We have reviewed your March 19, 2020 response to our comment letter and
have the
following comments. In some of our comments, we may ask you to provide us with
information
so we may better understand your disclosure.

       Please respond to these comments within ten business days by providing
the requested
information or advise us as soon as possible when you will respond. If you do
not believe our
comments apply to your facts and circumstances, please tell us why in your
response.

      After reviewing your response to these comments, we may have additional
comments. Unless we note otherwise, our references to prior comments are to
comments in
our March 6, 2020 letter.

Form 10-K for the Fiscal Year Ended December 31, 2019

Critical Accounting Policies
Depreciable Lives of Property, Plant and Equipment (All Registrants), page 78

1.    We have read your response to comment 2. We note from your disclosure on
page 272
      that you increased your asset retirement obligation by $780 million in
part due to changes
      in the assumed retirement timing probabilities of economically challenged
nuclear plants.
      In this regard, it appears that you revised the planned asset retirement
dates of the nuclear
      plants that are economically challenged. Your proposed disclosure
indicates that when a
      determination has been made that an asset will be retired before the end
of its current
      estimated useful life, depreciation provisions will be accelerated to
reflect the shortened
 Fabian Souza
EXELON CORP
April 3, 2020
Page 2
         estimated useful life, which could have a material unfavorable impact
on Exelon's and
         Generation's future results of operations. A company should address
specifically why its
         accounting estimates or assumptions bear the risk of change. The
reason may be that there
         is an uncertainty attached to the estimate or assumption, or it just
may be difficult to
         measure or value. Equally important, companies should address the
questions that arise
         once the critical accounting estimate or assumption has been
identified, by analyzing, to
         the extent material, such factors as how they arrived at the estimate,
how accurate the
         estimate/assumption has been in the past, how much the
estimate/assumption has changed
         in the past, and whether the estimate/assumption is reasonably likely
to change in the
         future. Since critical accounting estimates and assumptions are based
on matters that are
         highly uncertain, a company should analyze their specific sensitivity
to change, based on
         outcomes that are reasonably likely to occur and would have a material
effect. Please note
         a Company is required to provide quantitative as well as qualitative
disclosure when
         quantitative information is reasonably available and will provide
material information for
         investors pursuant to Section V of SEC Release 33-8350. Please
disclose the accounting
         estimates or assumptions used to determine the depreciable lives of
your Dresden, Byron
         and Braidwood units at risk of early retirement, including their book
values, based on the
         guidance in SEC Release 33-8350.

Results of Operations by Registrant, page 84

2.       We have read your response to comment 3. It appears the Company's
chief operating
         decision maker ("CODM") uses net income as the segment measure for the
utility
         registrants. Please reconcile the non-GAAP measure revenues net of
purchased power
         and fuel expense ("RNF") to a GAAP gross margin that includes
depreciation and
         amortization expense for the utility registrants. In this regard, a
GAAP gross margin
         should be used as the starting point of the non-GAAP reconciliation of
RNF and should be
         shown even if it is not otherwise presented in the utility registrants
financial statements.


        You may contact Robert Babula, Senior Staff Accountant at (202)
551-3339, or Gus
Rodriguez, Branch Chief at (202) 551-3752 if you have questions regarding
comments on the
financial statements and related matters.



FirstName LastNameFabian Souza                                 Sincerely,
Comapany NameEXELON CORP
                                                               Division of
Corporation Finance
April 3, 2020 Page 2                                           Office of Energy
& Transportation
FirstName LastName