CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
OPERATING REVENUES	$ 620,631	$ 648,847
OPERATING EXPENSES
Fuel and purchased power	216,309	212,007
Operations and maintenance	210,663	255,029
Depreciation and amortization	100,109	106,583
Taxes other than income taxes	42,475	37,624
Other expenses	3,068	1,820
Total	572,624	613,063
OPERATING INCOME	48,007	35,784
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	4,756	5,395
Other income (Note 11)	760	1,690
Other expense (Note 11)	(4,068)	(1,741)
Total	1,448	5,344
INTEREST EXPENSE
Interest charges	56,967	61,077
Allowance for borrowed funds used during construction	(3,151)	(3,576)
Total	53,816	57,501
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(4,361)	(16,373)
INCOME TAXES	(4,645)	(6,005)
INCOME (LOSS) FROM CONTINUING OPERATIONS	284	(10,368)
INCOME (LOSS) FROM DISCONTINUED OPERATIONS
Net of income tax expense (benefit) of $(505) and $330 (Note 13)	(765)	694
NET INCOME (LOSS)	(481)	(9,674)
Less: Net income attributable to noncontrolling interests (Note 7)	7,776	5,461
NET LOSS ATTRIBUTABLE TO COMMON SHAREHOLDERS	(8,257)	(15,135)
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	109,299	108,832
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	109,299	108,832
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Loss from continuing operations attributable to common shareholders - basic (in dollars per share)	$ (0.07)	$ (0.15)
Net loss attributable to common shareholders - basic (in dollars per share)	$ (0.08)	$ (0.14)
Loss from continuing operations attributable to common shareholders - diluted (in dollars per share)	$ (0.07)	$ (0.15)
Net loss attributable to common shareholders - diluted (in dollars per share)	$ (0.08)	$ (0.14)
DIVIDENDS DECLARED PER SHARE (in dollars per share)	$ 0.525	$ 0.525
AMOUNTS ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Loss from continuing operations, net of tax	(7,483)	(15,838)
Discontinued operations, net of tax	(774)	703
Net loss attributable to common shareholders	$ (8,257)	$ (15,135)