CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
OPERATING REVENUES
Regulated electricity	$ 1,124,049	$ 1,116,211	$ 2,570,692	$ 2,527,052
Other revenues	792	499	2,795	4,715
Total	1,124,841	1,116,710	2,573,487	2,531,767
OPERATING EXPENSES
Regulated electricity fuel and purchased power	337,896	353,904	793,952	821,244
Operations and maintenance	210,035	219,658	675,654	639,580
Depreciation and amortization	106,350	104,177	319,550	307,806
Taxes other than income taxes	34,223	37,528	112,002	100,933
Other expenses	1,320	1,169	4,536	3,572
Total	689,824	716,436	1,905,694	1,873,135
OPERATING INCOME	435,017	400,274	667,793	658,632
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	7,378	5,524	18,697	16,417
Other income (Note 11)	441	4,261	2,630	3,851
Other expense (Note 11)	(3,052)	(3,894)	(7,921)	(8,768)
Total	4,767	5,891	13,406	11,500
INTEREST EXPENSE
Interest charges	62,034	60,419	183,251	181,937
Allowance for borrowed funds used during construction	(6,939)	(6,163)	(14,371)	(12,254)
Total	55,095	54,256	168,880	169,683
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	384,689	351,909	512,319	500,449
INCOME TAXES	131,416	122,347	176,229	165,882
INCOME FROM CONTINUING OPERATIONS	253,273	229,562	336,090	334,567
INCOME FROM DISCONTINUED OPERATIONS
Net of income tax expense of $6,216 and $5,859 for three months ended September 30, 2011 and 2010, $7,121 and $14,873 for nine months ended September 30, 2011 and 2010 (Note 13)	9,512	9,477	10,860	23,141
NET INCOME	262,785	239,039	346,950	357,708
Less: Net income attributable to noncontrolling interests (Note 7)	7,426	5,119	20,041	15,005
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	255,359	233,920	326,909	342,703
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	109,128	108,632	109,003	105,846
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	109,861	109,094	109,683	106,318
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Income from continuing operations attributable to common shareholders - basic (in dollars per share)	$ 2.25	$ 2.07	$ 2.90	$ 3.02
Net income attributable to common shareholders - basic (in dollars per share)	$ 2.34	$ 2.15	$ 3.00	$ 3.24
Income from continuing operations attributable to common shareholders - diluted (in dollars per share)	$ 2.24	$ 2.06	$ 2.88	$ 3.01
Net income attributable to common shareholders - diluted (in dollars per share)	$ 2.32	$ 2.14	$ 2.98	$ 3.22
DIVIDENDS DECLARED PER SHARE (in dollars per share)			$ 1.575	$ 1.575
AMOUNTS ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Income from continuing operations, net of tax	245,838	224,434	316,001	319,533
Discontinued operations, net of tax	9,521	9,486	10,908	23,170
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 255,359	$ 233,920	$ 326,909	$ 342,703