<TABLE> <S> <C>
<PAGE>
<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, OPERATIONS
STATEMENT, AND CASH FLOW STATEMENT OF ILLINOIS POWER COMPANY.
</LEGEND>
<MULTIPLIER> 1,000,000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> JUN-30-2000
<BOOK-VALUE> PER-BOOK
<TOTAL-NET-UTILITY-PLANT> 1,795
<OTHER-PROPERTY-AND-INVEST> 20
<TOTAL-CURRENT-ASSETS> 295
<TOTAL-DEFERRED-CHARGES> 2,559
<OTHER-ASSETS> 137
<TOTAL-ASSETS> 4,806
<COMMON> 980
<CAPITAL-SURPLUS-PAID-IN> 0
<RETAINED-EARNINGS> 101
<TOTAL-COMMON-STOCKHOLDERS-EQ> 1,081
100
46
<LONG-TERM-DEBT-NET> 1,831
<SHORT-TERM-NOTES> 0
<LONG-TERM-NOTES-PAYABLE> 0
<COMMERCIAL-PAPER-OBLIGATIONS> 125
<LONG-TERM-DEBT-CURRENT-PORT> 87
0
<CAPITAL-LEASE-OBLIGATIONS> 0
<LEASES-CURRENT> 0
<OTHER-ITEMS-CAPITAL-AND-LIAB> 1,536
<TOT-CAPITALIZATION-AND-LIAB> 4,806
<GROSS-OPERATING-REVENUE> 724
<INCOME-TAX-EXPENSE> (9)
<OTHER-OPERATING-EXPENSES> 662
<TOTAL-OPERATING-EXPENSES> 653
<OPERATING-INCOME-LOSS> 71
<OTHER-INCOME-NET> 55
<INCOME-BEFORE-INTEREST-EXPEN> 126
<TOTAL-INTEREST-EXPENSE> 71
<NET-INCOME> 55
9
<EARNINGS-AVAILABLE-FOR-COMM> 46
<COMMON-STOCK-DIVIDENDS> 0
<TOTAL-INTEREST-ON-BONDS> 59
<CASH-FLOW-OPERATIONS> 260
<EPS-BASIC> 0
<EPS-DILUTED> 0
</TABLE>
