Derivatives And Risk Management (Derivative Instruments Summary) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Gross Asset	$ 97,940,000	$ 99,045,000
Gross Liability	(250,991,000)	(229,790,000)
Collateral Netting	57,934,000	44,390,000
Net Asset (Liability) in Balance Sheet	(95,117,000)	(86,355,000)
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Collateral Netting	7,444,000	15,510,000
Other Current Liabilities [Member] \| Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	14,000	1,000
Gross Liability	(24,000)	(21,000)
Collateral Netting	0	0
Net Asset (Liability) in Balance Sheet	(10,000)	(20,000)
Other Current Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	0	0
Gross Liability	(12,819,000)	(7,325,000)
Collateral Netting	677,000	0
Net Asset (Liability) in Balance Sheet	(12,142,000)	(7,325,000)
Other Current Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset		966,000
Gross Liability		(506,000)
Collateral Netting		0
Net Asset (Liability) in Balance Sheet		460,000
Current Utility Energy Commodity Derivative Assets [Member] \| Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	41,898,000	2,063,000
Gross Liability	(40,319,000)	(538,000)
Collateral Netting	0	0
Net Asset (Liability) in Balance Sheet	1,579,000	1,525,000
Current Utility Energy Commodity Derivative Liabilities [Member] \| Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	22,658,000	66,421,000
Gross Liability	(40,298,000)	(97,586,000)
Collateral Netting	3,462,000	13,120,000
Net Asset (Liability) in Balance Sheet	(14,178,000)	(18,045,000)
Other Noncurrent Liabilities [Member] \| Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	0	0
Gross Liability	(100,016,000)	(69,737,000)
Collateral Netting	49,813,000	28,880,000
Net Asset (Liability) in Balance Sheet	(50,203,000)	(40,857,000)
Other Noncurrent Liabilities [Member] \| Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	33,370,000	29,594,000
Gross Liability	(57,515,000)	(54,077,000)
Collateral Netting	3,982,000	2,390,000
Net Asset (Liability) in Balance Sheet	$ (20,163,000)	$ (22,093,000)

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

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-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

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