Restructuring Restructuring Expected Costs, Costs To-Date, Remaining Costs, and Costs During the Period - 2013 Projects (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended							9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Employee severance costs	Sep. 30, 2014 Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]	Sep. 30, 2014 Other restructuring costs	Sep. 30, 2014 2013 Project [Member]	Dec. 31, 2013 2013 Project [Member]	Sep. 30, 2014 2013 Project [Member] Employee severance costs	Dec. 31, 2013 2013 Project [Member] Employee severance costs	Sep. 30, 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]	Sep. 30, 2014 2013 Project [Member] Other restructuring costs	Dec. 31, 2013 2013 Project [Member] Other restructuring costs	Sep. 30, 2014 2013 Project [Member] Electricity Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Electricity Operating Segment [Member]	Sep. 30, 2014 2013 Project [Member] Gas Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Gas Operating Segment [Member]	Sep. 30, 2014 2013 Project [Member] Water Operating Segment [Member]	Dec. 31, 2013 2013 Project [Member] Water Operating Segment [Member]	Sep. 30, 2014 2013 Project [Member] Corporate Unallocated [Member]	Dec. 31, 2013 2013 Project [Member] Corporate Unallocated [Member]
Restructuring Cost and Reserve [Line Items]
Total expected costs at period end								$ 28,888		$ 23,691		$ 1,232		$ 3,965		$ 15,512		$ 4,107		$ 3,130		$ 6,139
Restructuring and Related Cost, Cost Incurred to Date									31,099		29,186		1,232		681		24,056		4,369		1,957		717
Costs recognized during the period ended	58	28,379	(2,211)	32,777	(5,495)	0	3,284	(2,211)		(5,495)		0		3,284		(8,544)		(262)		1,173		5,422
Remaining Costs to be Recognized at Period End								$ 0		$ 0		$ 0		$ 0		$ 0		$ 0		$ 0		$ 0