Summary of Changes in Goodwill Assets (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Cost, beginning balance	$ 3,648,053	$ 3,647,539
Total Net, beginning balance	1,207,764	1,207,250
Goodwill from acquisitions	301
Reclassifications and other activity		86
Cost, ending balance	3,648,354	3,647,625
Total Net, ending balance	1,208,065	1,207,336
Accumulated Impairment	(2,440,289)	(2,440,289)	(2,440,289)	(2,440,289)
Regulated Unit
Goodwill [Line Items]
Cost, beginning balance	3,412,063	3,411,549
Goodwill from acquisitions	301
Reclassifications and other activity		86
Cost, ending balance	3,412,364	3,411,635
Accumulated Impairment	(2,332,670)	(2,332,670)	(2,332,670)	(2,332,670)
Market-Based Operations
Goodwill [Line Items]
Cost, beginning balance	235,990	235,990
Goodwill from acquisitions	0
Reclassifications and other activity		0
Cost, ending balance	235,990	235,990
Accumulated Impairment	$ (107,619)	$ (107,619)	$ (107,619)	$ (107,619)