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:
Electric, natural gas distribution and pipeline and energy services	$ 395,081	$ 477,481
Exploration and production, construction materials and contracting, construction services and other	457,726	424,324
Total operating revenues	852,807	901,805
Operating expenses:
Fuel and purchased power	18,420	16,954
Purchased natural gas sold	185,428	244,686
Operation and maintenance:
Electric, natural gas distribution and pipeline and energy services	68,401	67,963
Exploration and production, construction materials and contracting, construction services and other	376,146	359,797
Depreciation, depletion and amortization	85,380	84,674
Taxes, other than income	47,975	49,665
Total operating expenses	781,750	823,739
Operating income (loss)	71,057	78,066
Earnings from equity method investments	1,253	484
Other income	1,098	1,900
Interest expense	19,439	22,017
Income before income taxes	53,969	58,433
Income taxes	18,079	15,904
Income from continuing operations	35,890	42,529
Income (loss) from discontinued operations, net of tax	(100)	448
Net income	35,790	42,977
Dividends declared on preferred stocks	171	171
Earnings on common stock	$ 35,619	$ 42,806
Earnings (loss) per common share - basic:
Earnings Before Discontinued Operations	$ 0.19	$ 0.22
Discontinued Operations, Net of Tax	$ 0.00	$ 0.01
Earnings Per Common Share - Basic	$ 0.19	$ 0.23
Earnings (loss) per common share - diluted:
Earnings Before Discontinued Operations	$ 0.19	$ 0.22
Discontinued Operations, Net of Tax	$ 0.00	$ 0.01
Earnings Per Common Share - Diluted	$ 0.19	$ 0.23
Dividends declared per common share (in dollars per share)	$ 0.1675	$ 0.1625
Weighted average common shares outstanding - basic	188,811	188,671
Weighted average common shares outstanding - diluted	189,182	188,815