Derivatives And Risk Management (Derivative Instruments Summary) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Asset	$ 99,045,000	$ 89,132,000
Liability	(229,790,000)	(89,675,000)
Collateral Netting	44,390,000	8,732,000
Net Asset (Liability)	(86,355,000)	8,189,000
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Collateral Already Posted, Aggregate Fair Value	20,600,000	26,100,000
Other Current Liabilities [Member] \| Foreign Currency Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset	1,000
Liability	(21,000)
Collateral Netting	0
Net Asset (Liability)	(20,000)
Other Current Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset	0
Liability	(7,325,000)
Collateral Netting	0
Net Asset (Liability)	(7,325,000)
Other Current Liabilities [Member] \| Foreign Currency Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset		7,000
Liability		(6,000)
Collateral Netting		0
Net Asset (Liability)		1,000
Other Current Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset	966,000	13,968,000
Liability	(506,000)	0
Collateral Netting	0	0
Net Asset (Liability)	460,000	13,968,000
Other Property And Investments Net [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset		19,575,000
Liability		0
Collateral Netting		0
Net Asset (Liability)		19,575,000
Current Utility Energy Commodity Derivative Assets [Member] \| Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Asset	2,063,000	7,416,000
Liability	(538,000)	(4,394,000)
Collateral Netting	0	0
Net Asset (Liability)	1,525,000	3,022,000
Non-Current Utility Energy Commodity Derivative Assets [Member] \| Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Asset		7,610,000
Liability		(6,756,000)
Collateral Netting		0
Net Asset (Liability)		854,000
Current Utility Energy Commodity Derivative Liabilities [Member] \| Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Asset	66,421,000	23,455,000
Liability	(97,586,000)	(37,306,000)
Collateral Netting	13,120,000	2,976,000
Net Asset (Liability)	(18,045,000)	(10,875,000)
Other Noncurrent Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset	0
Liability	(69,737,000)
Collateral Netting	28,880,000
Net Asset (Liability)	(40,857,000)
Other Noncurrent Liabilities [Member] \| Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Asset	29,594,000	17,101,000
Liability	(54,077,000)	(41,213,000)
Collateral Netting	2,390,000	5,756,000
Net Asset (Liability)	$ (22,093,000)	$ (18,356,000)

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (d)

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a master netting arrangement.

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