EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended	6 Months Ended
Apr. 09, 2012	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2011
Earnings Per Share Basic And Diluted [Line Items]
Net Income Attributable to Controlling Interests			$ 44,339		$ 77,278		$ 143,601		$ 191,433
Basic		301,047,753	301,047,753	177,347,374	177,347,374	239,551,735	239,551,735	177,267,791	177,267,791
Weighted Average Number Diluted Shares Outstanding Adjustment		769,131	769,131	279,618	279,618	575,434	575,434	286,204	286,204
Diluted		301,816,884	301,816,884	177,626,992	177,626,992	240,127,169	240,127,169	177,553,995	177,553,995
Earnings Per Share Basic And Diluted		0.15	0.15	0.44	0.44	0.60	0.60	1.08	1.08
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount		17,065	17,065			8,533	8,533
Common Stock Issuance, Merger with NSTAR [Abstract]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	136,049,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Name Accounting Standards Codification

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Diluted Earnings Per Share

-URI http://asc.fasb.org/extlink&oid=6510752

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+ Details

- Definition

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References+ Details

- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References+ Details

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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+ Details