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
Revenues
Total revenues	$ 794,319	$ 655,664	$ 1,504,952	$ 1,274,704
Expenses
Total expenses	730,658	592,033	1,377,916	1,150,366
Operating income (loss)
Total operating income (loss)	63,661	63,631	127,036	124,338
Interest expense-other than on deposit liabilities and other bank borrowings	(24,177)	(20,520)	(44,317)	(40,901)
Allowance for borrowed funds used during construction	553	790	1,073	1,569
Allowance for equity funds used during construction	1,317	1,847	2,561	3,620
Income before income taxes	41,354	45,748	86,353	88,626
Income taxes	13,742	16,013	29,806	31,292
Net income	27,612	29,735	56,547	57,334
Preferred stock dividends of subsidiaries	473	473	946	946
Net income for common stock	27,139	29,262	55,601	56,388
Basic earnings per common share (in dollars per share)	$ 0.28	$ 0.31	$ 0.58	$ 0.61
Diluted earnings per common share (in dollars per share)	$ 0.28	$ 0.31	$ 0.58	$ 0.61
Dividends per common share (in dollars per share)	$ 0.31	$ 0.31	$ 0.62	$ 0.62
Weighted-average number of common shares outstanding (in shares)	95,393	93,159	95,107	92,867
Dilutive effect of share-based compensation (in shares)	162	255	287	292
Adjusted weighted-average shares (in shares)	95,555	93,414	95,394	93,159
Electric utility
Revenues
Total revenues	728,738	584,095	1,374,073	1,132,206
Expenses
Total expenses	686,220	542,660	1,286,347	1,048,162
Operating income (loss)
Total operating income (loss)	42,518	41,435	87,726	84,044
Income before income taxes	28,603	28,354	59,870	57,866
Income taxes	11,080	10,213	22,659	21,174
Net income	17,523	18,141	37,211	36,692
Preferred stock dividends of subsidiaries	499	499	998	998
Net income for common stock	17,024	17,642	36,213	35,694
Bank
Revenues
Total revenues	66,318	71,632	131,631	142,546
Expenses
Total expenses	42,498	45,857	86,057	95,000
Operating income (loss)
Total operating income (loss)	23,820	25,775	45,574	47,546
Income before income taxes	23,806	25,747	45,533	47,483
Income taxes	8,611	9,616	16,487	17,616
Net income	15,195	16,131	29,046	29,867
Net income for common stock	15,195	16,131	29,046	29,867
Other
Revenues
Total revenues	(737)	(63)	(752)	(48)
Expenses
Total expenses	1,940	3,516	5,512	7,204
Operating income (loss)
Total operating income (loss)	(2,677)	(3,579)	(6,264)	(7,252)
Income before income taxes	(11,055)	(8,353)	(19,050)	(16,723)
Income taxes	(5,949)	(3,816)	(9,340)	(7,498)
Net income	(5,106)	(4,537)	(9,710)	(9,225)
Preferred stock dividends of subsidiaries	(26)	(26)	(52)	(52)
Net income for common stock	$ (5,080)	$ (4,511)	$ (9,658)	$ (9,173)