Business segment data

12 Months Ended

Dec. 31, 2012

Segment Reporting [Abstract]

Business segment data

Business Segment Data

The Company's reportable segments are those that are based on the Company's method of internal reporting, which generally segregates the strategic business units due to differences in products, services and regulation. The internal reporting of these operating segments is defined based on the reporting and review process used by the Company's chief executive officer and other management. The vast majority of the Company's operations are located within the United States. The Company also has an investment in a foreign country, which consists of Centennial Resources' equity method investment in ECTE.

The electric segment generates, transmits and distributes electricity in Montana, North Dakota, South Dakota and Wyoming. The natural gas distribution segment distributes natural gas in those states as well as in Idaho, Minnesota, Oregon and Washington. These operations also supply related value-added services.

The pipeline and energy services segment provides natural gas transportation, underground storage, processing and gathering services, as well as oil gathering, through regulated and nonregulated pipeline systems primarily in the Rocky Mountain and northern Great Plains regions of the United States. This segment also provides cathodic protection and other energy-related services.

The exploration and production segment is engaged in oil and natural gas acquisition, exploration, development and production activities in the Rocky Mountain and Mid-Continent regions of the United States and in and around the Gulf of Mexico.

The construction materials and contracting segment mines aggregates and markets crushed stone, sand, gravel and related construction materials, including ready-mixed concrete, cement, asphalt, liquid asphalt and other value-added products. It also performs integrated contracting services. This segment operates in the central, southern and western United States and Alaska and Hawaii.

The construction services segment specializes in constructing and maintaining electric and communication lines, gas pipelines, fire suppression systems, and external lighting and traffic signalization equipment. This segment also provides utility excavation services and inside electrical wiring, cabling and mechanical services, sells and distributes electrical materials, and manufactures and distributes specialty equipment.

The Other category includes the activities of Centennial Capital, which insures various types of risks as a captive insurer for certain of the Company's subsidiaries. The function of the captive insurer is to fund the deductible layers of the insured companies' general liability and automobile liability coverages. Centennial Capital also owns certain real and personal property. The Other category also includes Centennial Resources' equity method investment in ECTE.

The information below follows the same accounting policies as described in the Summary of Significant Accounting Policies. Information on the Company's businesses as of December 31 and for the years then ended was as follows:

	2012			2011			2010
	(In thousands)
External operating revenues:
Electric	$	236,895		$	225,468		$	211,544
Natural gas distribution	754,848			907,400			892,708
Pipeline and energy services	139,883			210,846			254,776
	1,131,626			1,343,714			1,359,028
Exploration and production	412,651			359,873			318,570
Construction materials and contracting	1,597,257			1,509,538			1,445,148
Construction services	932,013			834,918			786,802
Other	1,884			2,449			147
	2,943,805			2,706,778			2,550,667
Total external operating revenues	$	4,075,431		$	4,050,492		$	3,909,695
Intersegment operating revenues:
Electric	$	—		$	—		$	—
Natural gas distribution	—			—			—
Pipeline and energy services	53,274			67,497			75,033
Exploration and production	35,966			93,713			115,784
Construction materials and contracting	20,168			472			—
Construction services	6,545			19,471			2,298
Other	8,486			8,997			7,580
Intersegment eliminations	(124,439		)	(190,150		)	(200,695		)
Total intersegment operating revenues	$	—		$	—		$	—
Depreciation, depletion and amortization:
Electric	$	32,509		$	32,177		$	27,274
Natural gas distribution	45,731			44,641			43,044
Pipeline and energy services	27,684			25,502			26,001
Exploration and production	160,681			142,645			130,455
Construction materials and contracting	79,527			85,459			88,331
Construction services	11,063			11,399			12,147
Other	2,010			1,572			1,591
Total depreciation, depletion and amortization	$	359,205		$	343,395		$	328,843

	2012			2011			2010
	(In thousands)
Interest expense:
Electric	$	12,421		$	13,745		$	12,216
Natural gas distribution	28,726			29,444			28,996
Pipeline and energy services	7,742			10,516			9,064
Exploration and production	9,018			7,445			8,580
Construction materials and contracting	15,211			16,241			19,859
Construction services	4,435			4,473			4,411
Other	13			—			47
Intersegment eliminations	(867		)	(510		)	(162		)
Total interest expense	$	76,699		$	81,354		$	83,011
Income taxes:
Electric	$	8,975		$	7,242		$	11,187
Natural gas distribution	12,005			16,931			12,171
Pipeline and energy services	15,291			12,912			13,933
Exploration and production	(108,264		)	46,298			49,034
Construction materials and contracting	14,099			11,227			13,822
Construction services	24,128			13,426			11,456
Other	2,620			2,238			10,927
Total income taxes	$	(31,146	)	$	110,274		$	122,530
Earnings (loss) on common stock:
Electric	$	30,634		$	29,258		$	28,908
Natural gas distribution	29,409			38,398			36,944
Pipeline and energy services	26,588			23,082			23,208
Exploration and production	(177,283		)	80,282			85,638
Construction materials and contracting	32,420			26,430			29,609
Construction services	38,429			21,627			17,982
Other	4,797			6,190			21,046
Earnings (loss) on common stock before income (loss) from discontinued operations	(15,006		)	225,267			243,335
Income (loss) from discontinued operations, net of tax*	13,567			(12,926		)	(3,361		)
Total earnings (loss) on common stock	$	(1,439	)	$	212,341		$	239,974
Capital expenditures:
Electric	$	112,035		$	52,072		$	85,787
Natural gas distribution	130,178			70,624			75,365
Pipeline and energy services	133,787			45,556			14,255
Exploration and production	554,528			272,855			355,845
Construction materials and contracting	45,083			52,303			25,724
Construction services	14,835			9,711			14,849
Other	791			18,759			2,182
Net proceeds from sale or disposition of property and other	(57,460		)	(40,857		)	(78,761		)
Total net capital expenditures	$	933,777		$	481,023		$	495,246
Assets:
Electric**	$	760,324		$	672,940		$	643,636
Natural gas distribution**	1,703,459			1,679,091			1,632,012
Pipeline and energy services	622,470			526,797			523,075
Exploration and production	1,539,017			1,481,556			1,342,808
Construction materials and contracting	1,371,252			1,374,026			1,382,836
Construction services	429,547			418,519			387,627
Other***	256,422			403,196			391,555
Total assets	$	6,682,491		$	6,556,125		$	6,303,549

	2012		2011		2010
	(In thousands)
Property, plant and equipment:
Electric**	$	1,150,584	$	1,068,524	$	1,027,034
Natural gas distribution**	1,689,950		1,568,866		1,508,845
Pipeline and energy services	816,533		719,291		683,807
Exploration and production	2,764,560		2,615,146		2,356,938
Construction materials and contracting	1,504,981		1,499,852		1,486,375
Construction services	130,624		124,796		122,940
Other	50,519		49,747		32,564
Less accumulated depreciation, depletion and amortization	3,608,912		3,361,208		3,103,323
Net property, plant and equipment	$	4,498,839	$	4,285,014	$	4,115,180

    * Reflected in the Other category.

  ** Includes allocations of common utility property.

*** Includes assets not directly assignable to a business (i.e. cash and cash equivalents, certain accounts receivable, certain investments and other miscellaneous current and deferred assets).

Note: The results reflect $391.8 million ($246.8 million after tax) of noncash write-downs of oil and natural gas properties in 2012.

Excluding the natural gas gathering arbitration charge of $16.5 million (after tax) in 2010, and the reversal of this arbitration charge of $15.0 million (after tax) in 2012, as discussed in Note 19, earnings from electric, natural gas distribution and pipeline and energy services are substantially all from regulated operations. Earnings from exploration and production, construction materials and contracting, construction services and other are all from nonregulated operations.

Capital expenditures for 2012, 2011 and 2010 include noncash transactions, including capital expenditure-related accounts payable. The net noncash transactions were $33.7 million in 2012, $24.0 million in 2011 and $17.5 million in 2010.