Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating revenues:
Electric, natural gas distribution and regulated pipeline and midstream	$ 206,052	$ 215,678	$ 591,918	$ 622,167
Nonregulated pipeline and midstream, construction materials and contracting, construction services and other	837,896	722,361	1,312,245	1,176,717
Total operating revenues	1,043,948	938,039	1,904,163	1,798,884
Operating expenses:
Fuel and purchased power	15,914	19,327	37,925	43,146
Purchased natural gas sold	47,439	66,590	208,474	267,739
Operation and maintenance:
Electric, natural gas distribution and regulated pipeline and midstream	77,078	70,258	151,703	138,800
Nonregulated pipeline and midstream, construction materials and contracting, construction services and other	722,742	635,781	1,165,243	1,059,612
Depreciation, depletion and amortization	54,248	51,336	109,132	102,922
Taxes, other than income	37,562	35,038	80,736	76,648
Total operating expenses	954,983	878,330	1,753,213	1,688,867
Operating income	88,965	59,709	150,950	110,017
Other income	872	2,123	1,921	2,373
Interest expense	22,219	23,389	45,087	46,456
Income before income taxes	67,618	38,443	107,784	65,934
Income taxes	21,320	12,382	29,620	19,333
Income from continuing operations	46,298	26,061	78,164	46,601
Loss from discontinued operations, net of tax (Note 10)	(276,102)	(263,419)	(294,138)	(593,404)
Net loss	(229,804)	(237,358)	(215,974)	(546,803)
Loss from discontinued operations attributable to noncontrolling interest (Note 10)	(120,651)	(7,754)	(131,691)	(11,282)
Dividends declared on preferred stocks	171	171	343	342
Loss on common stock	$ (109,324)	$ (229,775)	$ (84,626)	$ (535,863)
Earnings (loss) per common share - basic:
Earnings before discontinued operations	$ 0.24	$ 0.13	$ 0.40	$ 0.24
Discontinued operations attributable to the Company, net of tax	(0.80)	(1.31)	(0.83)	(2.99)
Earnings (loss) per common share - basic	(0.56)	(1.18)	(0.43)	(2.75)
Earnings (loss) per common share - diluted:
Earnings before discontinued operations	0.24	0.13	0.40	0.24
Discontinued operations attributable to the Company, net of tax	(0.80)	(1.31)	(0.83)	(2.99)
Earnings (loss) per common share - diluted	(0.56)	(1.18)	(0.43)	(2.75)
Dividends declared per common share	$ 0.1875	$ 0.1825	$ 0.3750	$ 0.3650
Weighted average common shares outstanding - basic	195,304	194,805	195,294	194,643
Weighted average common shares outstanding - diluted	195,699	194,838	195,678	194,675