Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating revenues:
Electric, natural gas distribution and pipeline and energy services	$ 211,536	$ 192,103	$ 957,769	$ 843,670
Exploration and production, construction materials and contracting, construction services and other	1,158,919	1,093,679	2,549,585	2,434,310
Total operating revenues	1,370,455	1,285,782	3,507,354	3,277,980
Operating expenses:
Fuel and purchased power	19,236	19,983	66,826	59,760
Purchased natural gas sold	47,718	35,826	377,024	305,268
Operation and maintenance:
Electric, natural gas distribution and pipeline and energy services	79,848	64,078	225,180	206,808
Exploration and production, construction materials and contracting, construction services and other	897,887	870,252	2,002,884	1,925,762
Depreciation, depletion and amortization	103,497	99,966	306,180	288,816
Taxes, other than income	45,504	45,804	150,657	145,784
Total operating expenses	1,193,690	1,135,909	3,128,751	2,932,198
Operating income	176,765	149,873	378,603	345,782
Loss from equity method investments	(97)	(61)	(343)	(380)
Other income	2,644	2,326	7,552	5,003
Interest expense	22,425	21,012	64,912	63,312
Income before income taxes	156,887	131,126	320,900	287,093
Income taxes	54,769	46,576	109,818	99,559
Income from continuing operations	102,118	84,550	211,082	187,534
Income (loss) from discontinued operations, net of tax (Note 12)	3	(118)	506	(254)
Net income	102,121	84,432	211,588	187,280
Net loss attributable to noncontrolling interest	(1,088)	(24)	(2,390)	(204)
Dividends declared on preferred stocks	171	171	514	514
Earnings on common stock	$ 103,038	$ 84,285	$ 213,464	$ 186,970
Earnings per common share - basic:
Earnings before discontinued operations	$ 0.53	$ 0.45	$ 1.11	$ 0.99
Discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Earnings per common share - basic	$ 0.53	$ 0.45	$ 1.11	$ 0.99
Earnings per common share - diluted:
Earnings before discontinued operations	$ 0.53	$ 0.44	$ 1.11	$ 0.99
Discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Earnings per common share - diluted	$ 0.53	$ 0.44	$ 1.11	$ 0.99
Dividends declared per common share	$ 0.1775	$ 0.1725	$ 0.5325	$ 0.5175
Weighted average common shares outstanding - basic	193,949	188,831	191,958	188,831
Weighted average common shares outstanding - diluted	194,300	189,638	192,307	189,634