CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
OPERATING REVENUES
Regulated electricity segment	$ 798,669	$ 799,416	$ 1,446,643	$ 1,410,841
Other revenues	1,130	3,379	2,003	4,216
Total	799,799	802,795	1,448,646	1,415,057
OPERATING EXPENSES
Regulated electricity segment fuel and purchased power	244,049	251,800	456,056	467,340
Operations and maintenance	210,590	213,609	465,619	419,922
Depreciation and amortization	106,617	102,995	213,200	203,629
Taxes other than income taxes	40,155	31,682	77,779	63,405
Other expenses	1,396	1,325	3,216	2,403
Total	602,807	601,411	1,215,870	1,156,699
OPERATING INCOME	196,992	201,384	232,776	258,358
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	5,924	5,504	11,319	10,893
Other income (Note 11)	557	943	2,247	1,892
Other expense (Note 11)	(3,186)	(5,650)	(4,927)	(7,176)
Total	3,295	797	8,639	5,609
INTEREST EXPENSE
Interest charges	60,140	60,751	121,217	121,518
Allowance for borrowed funds used during construction	(3,856)	(3,072)	(7,432)	(6,091)
Total	56,284	57,679	113,785	115,427
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	144,003	144,502	127,630	148,540
INCOME TAXES	50,818	51,188	44,813	43,535
INCOME FROM CONTINUING OPERATIONS	93,185	93,314	82,817	105,005
INCOME FROM DISCONTINUED OPERATIONS
Net of income tax expense of $773 and $16,922 for three months ended and $906 and $9,013 for six months ended June 30, 2011 and 2010, respectively (Note 13)	654	26,252	1,348	13,664
NET INCOME	93,839	119,566	84,165	118,669
Less: Net income attributable to noncontrolling interests (Note 7)	7,154	4,769	12,615	9,886
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	86,685	114,797	71,550	108,783
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	109,044	107,355	108,939	104,431
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	109,718	107,764	109,540	104,857
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Income from continuing operations attributable to common shareholders - basic (in dollars per share)	$ 0.79	$ 0.82	$ 0.64	$ 0.91
Net income attributable to common shareholders - basic (in dollars per share)	$ 0.80	$ 1.07	$ 0.66	$ 1.04
Income from continuing operations attributable to common shareholders - diluted (in dollars per share)	$ 0.78	$ 0.82	$ 0.64	$ 0.91
Net income attributable to common shareholders - diluted (in dollars per share)	$ 0.79	$ 1.07	$ 0.65	$ 1.04
DIVIDENDS DECLARED PER SHARE (in dollars per share)	$ 1.05	$ 1.05	$ 1.575	$ 1.575
AMOUNTS ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Income from continuing operations, net of tax	86,001	88,536	70,163	95,099
Discontinued operations, net of tax	684	26,261	1,387	13,684
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 86,685	$ 114,797	$ 71,550	$ 108,783