<TABLE> <S> <C>
<PAGE>
<ARTICLE> UT
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-END> SEP-30-2000
<BOOK-VALUE> PER-BOOK
<TOTAL-NET-UTILITY-PLANT> 2,291,800
<OTHER-PROPERTY-AND-INVEST> 90,300
<TOTAL-CURRENT-ASSETS> 381,900
<TOTAL-DEFERRED-CHARGES> 184,100
<OTHER-ASSETS> 1,492,900
<TOTAL-ASSETS> 4,441,000
<COMMON> 1,300
<CAPITAL-SURPLUS-PAID-IN> (22,300)
<RETAINED-EARNINGS> 793,500
<TOTAL-COMMON-STOCKHOLDERS-EQ> 772,500
550,100
22,900
<LONG-TERM-DEBT-NET> 1,753,500
<SHORT-TERM-NOTES> 0
<LONG-TERM-NOTES-PAYABLE> 0
<COMMERCIAL-PAPER-OBLIGATIONS> 223,200
<LONG-TERM-DEBT-CURRENT-PORT> 0
0
<CAPITAL-LEASE-OBLIGATIONS> 0
<LEASES-CURRENT> 0
<OTHER-ITEMS-CAPITAL-AND-LIAB> 1,118,800
<TOT-CAPITALIZATION-AND-LIAB> 4,441,000
<GROSS-OPERATING-REVENUE> 1,056,900
<INCOME-TAX-EXPENSE> 70,500
<OTHER-OPERATING-EXPENSES> 723,800
<TOTAL-OPERATING-EXPENSES> 794,300
<OPERATING-INCOME-LOSS> 262,600
<OTHER-INCOME-NET> (4,500)
<INCOME-BEFORE-INTEREST-EXPEN> 258,100
<TOTAL-INTEREST-EXPENSE> 179,700
<NET-INCOME> 78,400
700
<EARNINGS-AVAILABLE-FOR-COMM> 77,700
<COMMON-STOCK-DIVIDENDS> 93,100
<TOTAL-INTEREST-ON-BONDS> 124,800
<CASH-FLOW-OPERATIONS> 193,900
<EPS-BASIC> .60
<EPS-DILUTED> .58
</TABLE>