Consolidated Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated provision for uncollectible accounts - customers
Consolidated Valuation and Qualifying Accounts
Beginning Balance	$ 51,630	$ 40,354	$ 37,303
Charged to Income	90,144	68,733	84,026
Charged to Other Accounts	36,373	39,775	36,686
Deductions	118,881	97,232	117,661
Ending Balance	59,266	51,630	40,354
Accumulated provision for uncollectible accounts - customers \| FES
Consolidated Valuation and Qualifying Accounts
Beginning Balance	11,073	16,188	16,441
Charged to Income	21,942	14,294	10,410
Charged to Other Accounts	0	0	0
Deductions	15,153	19,409	10,663
Ending Balance	17,862	11,073	16,188
Accumulated provision for uncollectible accounts - other
Consolidated Valuation and Qualifying Accounts
Beginning Balance	2,976	4,013	3,447
Charged to Income	3,469	(1,464)	4,328
Charged to Other Accounts	8,264	5,208	203
Deductions	9,512	4,781	3,965
Ending Balance	5,197	2,976	4,013
Accumulated provision for uncollectible accounts - other \| FES
Consolidated Valuation and Qualifying Accounts
Beginning Balance	2,523	2,500	2,500
Charged to Income	9	28	1,290
Charged to Other Accounts	0	0	0
Deductions	32	5	1,290
Ending Balance	2,500	2,523	2,500
Loss carryforward tax valuation reserve
Consolidated Valuation and Qualifying Accounts
Beginning Balance	125,360	101,697	34,236
Charged to Income	48,644	23,663	67,461
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Ending Balance	174,004	125,360	101,697
Loss carryforward tax valuation reserve \| FES
Consolidated Valuation and Qualifying Accounts
Beginning Balance	26,875	15,810	11,650
Charged to Income	5,251	11,065	4,160
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Ending Balance	$ 32,126	$ 26,875	$ 15,810

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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- Definition

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+ References

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