Restructuring Restructuring Expected Costs, Costs To-Date, Remaining Costs, and Costs During the Period - 2013 Projects (Details) (USD $)	3 Months Ended						4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended	3 Months Ended	4 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Employee severance costs	Mar. 31, 2014 Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]	Mar. 31, 2014 Other restructuring costs	Mar. 31, 2014 2013 Project [Member]	Dec. 31, 2013 2013 Project [Member]	Mar. 31, 2014 2013 Project [Member] Employee severance costs	Dec. 31, 2013 2013 Project [Member] Employee severance costs	Mar. 31, 2014 2013 Project [Member] Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]	Dec. 31, 2013 2013 Project [Member] Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]	Mar. 31, 2014 2013 Project [Member] Other restructuring costs	Dec. 31, 2013 2013 Project [Member] Other restructuring costs	Mar. 31, 2014 2013 Project [Member] Electricity Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Electricity Operating Segment [Member]	Mar. 31, 2014 2013 Project [Member] Gas Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Gas Operating Segment [Member]	Mar. 31, 2014 2013 Project [Member] Water Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Water Operating Segment [Member]	Mar. 31, 2014 2013 Project [Member] Corporate Unallocated [Member]	Dec. 31, 2013 2013 Project [Member] Corporate Unallocated [Member]
Restructuring Cost and Reserve [Line Items]
Change in Total Expected Restructuring Costs						$ 5,800,000
Total expected costs at period end						37,123,000		33,381,000		1,232,000		2,510,000		23,526,000		4,066,000		2,514,000		7,017,000
Restructuring and Related Cost, Cost Incurred to Date							31,099,000		29,186,000		1,232,000		681,000		24,056,000		4,369,000		1,957,000		717,000
Costs recognized during the period ended	5,524,000	1,013,000	4,195,000	0	1,329,000	5,524,000		4,195,000		0		1,329,000		(530,000)		(303,000)		557,000		5,800,000
Remaining Costs to be Recognized at Period End						$ 500,000		$ 0		$ 0		$ 500,000		$ 0		$ 0		$ 0		$ 500,000