XML 71 R49.htm IDEA: XBRL DOCUMENT v2.4.0.6
Business segment data (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Segment Reporting Information [Line Items]        
Total external operating revenues $ 1,173,518 $ 1,152,181 $ 2,994,288 $ 2,984,743
Total intersegment operating revenues 0 0 0 0
Earnings (loss) on common stock (29,842) 63,803 59,719 151,505
Regulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 184,863 212,848 784,399 964,866
Total intersegment operating revenues 7,046 10,591 36,393 47,836
Earnings (loss) on common stock 5,491 2,350 55,175 56,790
Unregulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 988,655 939,333 2,209,889 2,019,877
Total intersegment operating revenues 19,366 29,325 42,251 91,443
Earnings (loss) on common stock (35,333) 61,453 4,544 94,715
Electric [Member] | Regulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 63,492 61,949 174,410 169,780
Total intersegment operating revenues 0 0 0 0
Earnings (loss) on common stock 11,000 8,312 22,977 21,642
Natural gas distribution [Member] | Regulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 80,069 92,440 504,805 627,450
Total intersegment operating revenues 0 0 0 0
Earnings (loss) on common stock (8,782) (11,183) 10,314 18,235
Pipeline and energy services [Member] | Regulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 41,302 58,459 105,184 167,636
Total intersegment operating revenues 7,046 10,591 36,393 47,836
Earnings (loss) on common stock 3,273 5,221 21,884 16,913
Exploration and production [Member] | Unregulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 100,380 96,803 289,106 262,604
Total intersegment operating revenues 8,076 23,956 25,114 74,889
Earnings (loss) on common stock (87,748) 22,497 (56,860) 60,093
Construction materials and contracting [Member] | Unregulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 641,500 619,134 1,229,731 1,138,280
Total intersegment operating revenues 8,508 0 11,756 0
Earnings (loss) on common stock 41,889 33,103 24,748 16,680
Construction services [Member] | Unregulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 246,358 222,822 688,368 617,699
Total intersegment operating revenues 834 3,344 1,078 9,940
Earnings (loss) on common stock 9,863 5,044 29,951 15,815
Other [Member] | Unregulated Operation [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 417 574 2,684 1,294
Total intersegment operating revenues 1,948 2,025 4,303 6,614
Earnings (loss) on common stock 663 809 6,705 2,127
Intersegment Elimination [Member]
        
Segment Reporting Information [Line Items]        
Total external operating revenues 0 0 0 0
Total intersegment operating revenues (26,412) (39,916) (78,644) (139,279)
Earnings (loss) on common stock $ 0 $ 0 $ 0 $ 0