Restructuring Restructuring Expected Costs, Costs Recognized, and Remaining Costs to be Recognized - 2013 Project (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 35,497,000	$ 1,665,000	$ 68,082,000
Employee severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	31,840,000
Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	1,259,000
Other restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	2,398,000
2013 Project [Member]
Restructuring Cost and Reserve [Line Items]
Change in Total Expected Restructuring Costs	2,200,000
Restructuring and Related Cost, Expected Cost	31,349,000
Restructuring Charges	31,099,000
Restructuring and Related Cost, Expected Cost Remaining	250,000
Restructuring - Percent of Positions Expected to be Eliminated	9.00%
2013 Project [Member] | Employee severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	29,186,000
Restructuring Charges	29,186,000
Restructuring and Related Cost, Expected Cost Remaining	0
2013 Project [Member] | Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	1,232,000
Restructuring Charges	1,232,000
Restructuring and Related Cost, Expected Cost Remaining	0
2013 Project [Member] | Other restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	931,000
Restructuring Charges	681,000
Restructuring and Related Cost, Expected Cost Remaining	250,000
2013 Project [Member] | Electricity Operating Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	24,250,000
Restructuring Charges	24,056,000
Restructuring and Related Cost, Expected Cost Remaining	194,000
2013 Project [Member] | Gas Operating Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	4,404,000
Restructuring Charges	4,369,000
Restructuring and Related Cost, Expected Cost Remaining	35,000
2013 Project [Member] | Water Operating Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	1,973,000
Restructuring Charges	1,957,000
Restructuring and Related Cost, Expected Cost Remaining	16,000
2013 Project [Member] | Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	722,000
Restructuring Charges	717,000
Restructuring and Related Cost, Expected Cost Remaining	$ 5,000