Exhibit (12) Commonwealth Edison Company Form 10-Q File No. 1-1839 Commonwealth Edison Company and Subsidiary Companies Consolidated ----------------------------------------------------------------- Computation of Ratios of Earnings to Fixed Charges and Ratios of Earnings to Fixed Charges and Preferred and Preference Stock Dividend Requirements ---------------------------------------------------- (Thousands of Dollars) Twelve Months Ended ------------------------- Line March 31, December 31, No. 1998 1997 - ---- --------- ------------ 1 Net income (loss) before extraordinary item and cumulative effect of 2 change in accounting principle $(169,579) $(160,138) --------- --------- 3 Net provisions for income taxes and investment tax credits deferred 4 charged to- 5 Operations $ 295,449 $ 307,276 6 Other income (408,260) (405,819) --------- --------- 7 $(112,811) $ (98,543) --------- --------- 8 Fixed charges- 9 Interest on debt $ 476,248 $ 487,749 10 Estimated interest component of nuclear fuel and 11 other lease payments, rentals and other interest 72,739 70,468 12 Amortization of debt discount, premium and expense 19,385 21,951 13 ComEd-obligated mandatorily redeemable preferred securities dividend 14 requirements of subsidiary trusts holding solely ComEd's subordinated 15 debt securities 29,640 28,860 --------- --------- 16 $ 598,012 $ 609,028 --------- --------- 17 Preferred and preference stock dividend requirements- 18 Provisions for preferred and preference stock dividends $ 59,506 $ 60,486 19 Taxes on income required to meet provisions for 20 preferred and preference stock dividends 38,981 39,623 --------- --------- 21 $ 98,487 $ 100,109 --------- --------- 22 Fixed charges and preferred and preference stock 23 dividend requirements $ 696,499 $ 709,137 --------- --------- 24 Earned for fixed charges and preferred and preference stock 25 dividend requirements $ 315,622 $ 350,347 --------- --------- 26 Ratios of earnings to fixed charges (line 22 divided by line 13) 0.53 0.58 ==== ==== 27 Ratios of earnings to fixed charges and preferred and preference 28 stock dividend requirements (line 22 divided by line 20) 0.45 0.49 ==== ====