SUBSEQUENT EVENTS	12 Months Ended
Dec. 31, 2012
Notes To Consolidated Financial Statements [Abstract]
Subsequent Events [Text Block]	23. SUBSEQUENT EVENTS (NU, CL&P, NSTAR Electric) See Note 9, "Long-Term Debt" to the consolidated financial statements for information regarding the January 2013 long-term debt issuance for CL&P. See Note 12C, "Commitments and Contingencies – Deferred Contractual Obligations" to the consolidated financial statements for information regarding the receipt of the DOE proceeds by the Yankee Companies in January 2013. See Note 11, "Income Taxes," for discussion of the federal legislation enacted on January 2, 2013. On February 8, 2013, a blizzard caused damage to the electric delivery systems of CL&P and NSTAR Electric. Management believes that this storm will cost between $100 million to $120 million, with approximately 90 percent of those costs relating to NSTAR Electric. Management expects the costs to meet the criteria for specific cost recovery in Connecticut and Massachusetts and, as a result, does not expect the storm to have a material impact on the results of operations of CL&P or NSTAR Electric. Each operating company will seek recovery of these anticipated deferred storm costs through its applicable regulatory recovery process.

SUBSEQUENT EVENTS

12 Months Ended

Dec. 31, 2012

Notes To Consolidated Financial Statements [Abstract]

23. SUBSEQUENT EVENTS (NU, CL&P, NSTAR Electric)

See Note 9, "Long-Term Debt" to the consolidated financial statements for information regarding the January 2013 long-term debt issuance for CL&P.

See Note 12C, "Commitments and Contingencies – Deferred Contractual Obligations" to the consolidated financial statements for information regarding the receipt of the DOE proceeds by the Yankee Companies in January 2013.

See Note 11, "Income Taxes," for discussion of the federal legislation enacted on January 2, 2013.

On February 8, 2013, a blizzard caused damage to the electric delivery systems of CL&P and NSTAR Electric. Management believes that this storm will cost between $100 million to $120 million, with approximately 90 percent of those costs relating to NSTAR Electric. Management expects the costs to meet the criteria for specific cost recovery in Connecticut and Massachusetts and, as a result, does not expect the storm to have a material impact on the results of operations of CL&P or NSTAR Electric. Each operating company will seek recovery of these anticipated deferred storm costs through its applicable regulatory recovery process.