Amount of contributions made to multiemployer plans by the employer. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 80

-Section 50

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=14450570&loc=SL14450702-114947

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 80

-Section 50

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=14450570&loc=SL14450691-114947

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 80

-Section 50

-Paragraph 5

-Subparagraph (e)(1)

-URI http://asc.fasb.org/extlink&oid=14450570&loc=SL14450657-114947

Name:	us-gaap_MultiemployerPlanPeriodContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

PENSION AND OTHER SAVING PLANS - Multiemployer Plans (Details) (USD $) In Millions, unless otherwise specified		12 Months Ended
	Jan. 31, 2012	Dec. 31, 2013 WECO [Member]	Dec. 31, 2012 WECO [Member]	Dec. 31, 2011 WECO [Member]	Dec. 31, 2013 WRI [Member]	Dec. 31, 2012 WRI [Member]	Dec. 31, 2011 WRI [Member]	Dec. 31, 2013 WSC [Member]	Dec. 31, 2012 WSC [Member]	Dec. 31, 2011 WSC [Member]	Dec. 31, 2013 Minimum [Member] WSC [Member]	Dec. 31, 2013 Maximum [Member] WSC [Member]
Multiemployer Plans [Line Items]
Multiemployer Plans Funded Status Minimum Percentage	80.00%
Multiemployer Plan Minimum Contribution Per Hour Worked		5.75			5.70						2.95	3.20
Multiemployer Plan, Period Contributions		$ 3.4	$ 3.2	$ 3.2	$ 0.9	$ 0.5	$ 0.9	$ 0.1	$ 0.1	$ 0.1