CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
OPERATING REVENUES	$ 1,152,392	$ 1,109,475	$ 2,754,866	$ 2,608,682
OPERATING EXPENSES
Fuel and purchased power	350,953	302,894	859,216	783,926
Operations and maintenance	233,323	220,729	685,873	647,628
Depreciation and amortization	107,388	100,353	317,410	301,068
Taxes other than income taxes	43,256	36,507	124,091	120,271
Other expenses	1,784	1,022	5,853	5,323
Total	736,704	661,505	1,992,443	1,858,216
OPERATING INCOME	415,688	447,970	762,423	750,466
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	5,569	5,708	18,698	15,639
Other income (Note 10)	160	420	1,387	1,357
Other expense (Note 10)	(7,435)	(5,696)	(13,421)	(12,433)
Total	(1,706)	432	6,664	4,563
INTEREST EXPENSE
Interest charges	50,587	52,242	151,372	162,209
Allowance for borrowed funds used during construction	(3,235)	(3,830)	(10,861)	(10,428)
Total	47,352	48,412	140,511	151,781
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	366,630	399,990	628,576	603,248
INCOME TAXES	131,912	147,116	221,424	219,160
INCOME FROM CONTINUING OPERATIONS	234,718	252,874	407,152	384,088
LOSS FROM DISCONTINUED OPERATIONS
Net of income tax benefit of $7 for three months ended September 30, 2012 and $1,047 for nine months ended September 30, 2012		(11)		(1,595)
NET INCOME	234,718	252,863	407,152	382,493
Less: Net income attributable to noncontrolling interests (Note 6)	8,555	8,040	25,338	23,582
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	226,163	244,823	381,814	358,911
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	110,009	109,555	109,935	109,449
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	111,053	110,655	110,913	110,420
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Income from continuing operations attributable to common shareholders - basic (in dollars per share)	$ 2.06	$ 2.23	$ 3.47	$ 3.29
Net income attributable to common shareholders - basic (in dollars per share)	$ 2.06	$ 2.23	$ 3.47	$ 3.28
Income from continuing operations attributable to common shareholders - diluted (in dollars per share)	$ 2.04	$ 2.21	$ 3.44	$ 3.26
Net income attributable to common shareholders - diluted (in dollars per share)	$ 2.04	$ 2.21	$ 3.44	$ 3.25
DIVIDENDS DECLARED PER SHARE (in dollars per share)	$ 0.00		$ 1.09	$ 1.575
AMOUNTS ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Income from continuing operations, net of tax	226,163	244,834	381,814	360,515
Discontinued operations, net of tax		(11)		(1,604)
Net income attributable to common shareholders	$ 226,163	$ 244,823	$ 381,814	$ 358,911