<ARTICLE>                                           UT
<LEGEND>
     This schedule  contains summary  financial  information  extracted from the
balance  sheet,  income  statement,  and cash flow  statement of Illinois  Power
Company and is qualified  in its  entirety by  reference  to the balance  sheet,
income statement, and cash flow statement of Illinois Power Company.
</LEGEND>
<CIK>                                         0000049816
<NAME>                                        Illinois Power Company
<SUBSIDIARY>
   <NUMBER>                                   0
   <NAME>                                     0
<MULTIPLIER>                                   1,000,000
<CURRENCY>                                     Default

                             
<PERIOD-TYPE>                   6-mos
<FISCAL-YEAR-END>                              Dec-31-1999
<PERIOD-START>                                 Jan-01-1999
<PERIOD-END>                                   Jun-30-1999
<EXCHANGE-RATE>                                1
<BOOK-VALUE>                                   Per-Book
<TOTAL-NET-UTILITY-PLANT>                      4537
<OTHER-PROPERTY-AND-INVEST>                    3
<TOTAL-CURRENT-ASSETS>                         402
<TOTAL-DEFERRED-CHARGES>                       771
<OTHER-ASSETS>                                 0
<TOTAL-ASSETS>                                 5713
<COMMON>                                       893
<CAPITAL-SURPLUS-PAID-IN>                      0
<RETAINED-EARNINGS>                            16
<TOTAL-COMMON-STOCKHOLDERS-EQ>                 909
<PREFERRED-MANDATORY>                          194
<PREFERRED>                                    50
<LONG-TERM-DEBT-NET>                           2084
<SHORT-TERM-NOTES>                             80
<LONG-TERM-NOTES-PAYABLE>                      0
<COMMERCIAL-PAPER-OBLIGATIONS>                 0
<LONG-TERM-DEBT-CURRENT-PORT>                  272
<PREFERRED-STOCK-CURRENT>                      0
<CAPITAL-LEASE-OBLIGATIONS>                    53
<LEASES-CURRENT>                               16
<OTHER-ITEMS-CAPITAL-AND-LIAB>                 2055
<TOT-CAPITALIZATION-AND-LIAB>                  5713
<GROSS-OPERATING-REVENUE>                      850
<INCOME-TAX-EXPENSE>                           37
<OTHER-OPERATING-EXPENSES>                     707
<TOTAL-OPERATING-EXPENSES>                     744
<OPERATING-INCOME-LOSS>                        106
<OTHER-INCOME-NET>                             18
<INCOME-BEFORE-INTEREST-EXPEN>                 124
<TOTAL-INTEREST-EXPENSE>                       81
<NET-INCOME>                                   43
<PREFERRED-STOCK-DIVIDENDS>                    9
<EARNINGS-AVAILABLE-FOR-COMM>                  34
<COMMON-STOCK-DIVIDENDS>                       19
<TOTAL-INTEREST-ON-BONDS>                      55
<CASH-FLOW-OPERATIONS>                         38
<EPS-BASIC>                                  0
<EPS-DILUTED>                                  0