XML 73 R49.htm IDEA: XBRL DOCUMENT v3.3.1.900
Property, plant and equipment (Details 4) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Property, plant and equipment [Line Items]      
Interest capitalized $ 4,902 $ 8,586 $ 6,033
AFUDC - borrowed 4,907 3,022 2,767
AFUDC - equity 7,971 5,803 3,322
Property, plant and equipment 6,817,668 6,294,778  
Less accumulated depreciation, depletion and amortization 2,506,571 2,386,113 2,284,169
Net property, plant and equipment 4,311,097 3,908,665 3,461,553
Electric:      
Property, plant and equipment [Line Items]      
Property, plant and equipment [1] 1,786,148 1,457,101 1,315,822
Natural gas distribution:      
Property, plant and equipment [Line Items]      
Property, plant and equipment [1] 2,076,581 1,904,759 1,776,901
Pipeline and midstream:      
Property, plant and equipment [Line Items]      
Property, plant and equipment 758,729 818,388 789,569
Construction materials and contracting:      
Property, plant and equipment [Line Items]      
Property, plant and equipment 1,553,428 1,529,942 1,510,355
Construction services:      
Property, plant and equipment [Line Items]      
Property, plant and equipment 163,279 144,395 134,948
Refining      
Property, plant and equipment [Line Items]      
Property, plant and equipment 445,333 401,845 172,603
Other:      
Property, plant and equipment [Line Items]      
Property, plant and equipment 49,537 50,937 $ 49,997
Regulated: | Electric: | Generation      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 1,003,173 627,952  
Weighted average depreciable life in years 39 years    
Regulated: | Electric: | Distribution      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 375,612 343,692  
Weighted average depreciable life in years 44 years    
Regulated: | Electric: | Transmission      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 255,842 229,997  
Weighted average depreciable life in years 57 years    
Regulated: | Electric: | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 42,436 150,445  
Regulated: | Electric: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 109,085 105,015  
Weighted average depreciable life in years 14 years    
Regulated: | Natural gas distribution: | Distribution      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 1,624,645 1,481,390  
Weighted average depreciable life in years 35 years    
Regulated: | Natural gas distribution: | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 20,530 59,310  
Regulated: | Natural gas distribution: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 431,406 364,059  
Weighted average depreciable life in years 22 years    
Regulated: | Pipeline and midstream: | Transmission      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 460,305 449,276  
Weighted average depreciable life in years 53 years    
Regulated: | Pipeline and midstream: | Gathering      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 37,831 39,595  
Weighted average depreciable life in years 20 years    
Regulated: | Pipeline and midstream: | Storage      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 44,011 43,994  
Weighted average depreciable life in years 60 years    
Regulated: | Pipeline and midstream: | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 7,549 5,386  
Regulated: | Pipeline and midstream: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 40,168 39,910  
Weighted average depreciable life in years 33 years    
Nonregulated: | Eliminations      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ (15,367) (12,589)  
Nonregulated: | Pipeline and midstream: | Gathering and processing      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 158,949 227,598  
Weighted average depreciable life in years 16 years    
Nonregulated: | Pipeline and midstream: | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 89 691  
Nonregulated: | Pipeline and midstream: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 9,827 11,938  
Weighted average depreciable life in years 10 years    
Nonregulated: | Construction materials and contracting: | Land      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 123,723 125,372  
Nonregulated: | Construction materials and contracting: | Buildings and improvements      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 69,011 70,566  
Weighted average depreciable life in years 19 years    
Nonregulated: | Construction materials and contracting: | Machinery, vehicles and equipment      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 937,084 921,564  
Weighted average depreciable life in years 12 years    
Nonregulated: | Construction materials and contracting: | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 18,615 8,709  
Nonregulated: | Construction materials and contracting: | Aggregate reserves      
Property, plant and equipment [Line Items]      
Property, plant and equipment [2] 404,995 403,731  
Nonregulated: | Construction services: | Land      
Property, plant and equipment [Line Items]      
Property, plant and equipment 6,460 5,265  
Nonregulated: | Construction services: | Buildings and improvements      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 23,824 17,936  
Weighted average depreciable life in years 25 years    
Nonregulated: | Construction services: | Machinery, vehicles and equipment      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 121,940 112,973  
Weighted average depreciable life in years 6 years    
Nonregulated: | Construction services: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 11,055 8,221  
Weighted average depreciable life in years 3 years    
Nonregulated: | Refining | Construction in progress      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 135 313,613  
Nonregulated: | Refining | Refinery      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 445,198 88,232  
Weighted average depreciable life in years 20 years    
Nonregulated: | Other: | Land      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 2,837 2,837  
Nonregulated: | Other: | Other      
Property, plant and equipment [Line Items]      
Property, plant and equipment $ 46,700 $ 48,100  
Weighted average depreciable life in years 23 years    
[1] Includes allocations of common utility property
[2] Depleted on the units-of-production method.