SHORT-TERM AND LONG-TERM DEBT	3 Months Ended
Mar. 31, 2017
Debt Disclosure [Abstract]
SHORT-TERM AND LONG-TERM DEBT	SHORT-TERM AND LONG-TERM DEBT Commercial Paper Programs and Credit Agreements: Eversource parent has a $1.45 billion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. As of March 31, 2017 and December 31, 2016, Eversource parent had $801.0 million and approximately $1.0 billion, respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $649.0 million and $428.0 million of available borrowing capacity as of March 31, 2017 and December 31, 2016, respectively. The weighted-average interest rate on these borrowings as of March 31, 2017 and December 31, 2016 was 1.12 percent and 0.88 percent, respectively. As of March 31, 2017, there were intercompany loans from Eversource parent of $3.4 million to CL&P, $144.9 million to PSNH, and $71.4 million to WMECO. As of December 31, 2016, there were intercompany loans from Eversource parent of $80.1 million to CL&P, $160.9 million to PSNH and $51.0 million to WMECO. Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas are parties to a five-year $1.45 billion revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. There were no borrowings outstanding on the revolving credit facility as of March 31, 2017 or December 31, 2016. NSTAR Electric has a $450 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. As of March 31, 2017 and December 31, 2016, NSTAR Electric had $174.5 million and $126.5 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $275.5 million and $323.5 million of available borrowing capacity as of March 31, 2017 and December 31, 2016, respectively. The weighted-average interest rate on these borrowings as of March 31, 2017 and December 31, 2016 was 0.86 percent and 0.71 percent, respectively. NSTAR Electric is a party to a five-year $450 million revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop NSTAR Electric's $450 million commercial paper program. There were no borrowings outstanding on the revolving credit facility as of March 31, 2017 or December 31, 2016. Amounts outstanding under the commercial paper programs are included in Notes Payable for Eversource and NSTAR Electric and are classified in current liabilities on the balance sheets as all borrowings are outstanding for no more than 364 days at one time. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are included in Notes Payable to Eversource Parent and are classified in current liabilities on their respective balance sheets. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are eliminated in consolidation on Eversource's balance sheets. Long-Term Debt Issuances: In March 2017, Eversource parent issued $300 million of 2.75 percent Series K Senior Notes due to mature in 2022. The proceeds, net of issuance costs, were used to repay short-term borrowings under the Eversource parent commercial paper program. In March 2017, CL&P issued $300 million of 3.20 percent 2017 Series A First and Refunding Mortgage Bonds due to mature in 2027. The proceeds, net of issuance costs, were used to repay short-term borrowings. Long-Term Debt Repayments: In March 2017, CL&P repaid at maturity the $150 million 5.375 percent 2007 Series A First and Refunding Mortgage Bonds, using short term borrowings. Long-Term Debt Issuance Authorizations: On January 4, 2017, PURA approved CL&P's request for authorization to issue up to $1.325 billion in long-term debt through December 31, 2020. On March 30, 2017, the DPU approved NSTAR Electric's request for authorization to issue up to $700 million in long-term debt through December 31, 2018.

SHORT-TERM AND LONG-TERM DEBT

Commercial Paper Programs and Credit Agreements: Eversource parent has a $1.45 billion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. As of March 31, 2017 and December 31, 2016, Eversource parent had $801.0 million and approximately $1.0 billion, respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $649.0 million and $428.0 million of available borrowing capacity as of March 31, 2017 and December 31, 2016, respectively. The weighted-average interest rate on these borrowings as of March 31, 2017 and December 31, 2016 was 1.12 percent and 0.88 percent, respectively. As of March 31, 2017, there were intercompany loans from Eversource parent of $3.4 million to CL&P, $144.9 million to PSNH, and $71.4 million to WMECO. As of December 31, 2016, there were intercompany loans from Eversource parent of $80.1 million to CL&P, $160.9 million to PSNH and $51.0 million to WMECO. Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas are parties to a five-year $1.45 billion revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. There were no borrowings outstanding on the revolving credit facility as of March 31, 2017 or December 31, 2016.

NSTAR Electric has a $450 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. As of March 31, 2017 and December 31, 2016, NSTAR Electric had $174.5 million and $126.5 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $275.5 million and $323.5 million of available borrowing capacity as of March 31, 2017 and December 31, 2016, respectively. The weighted-average interest rate on these borrowings as of March 31, 2017 and December 31, 2016 was 0.86 percent and 0.71 percent, respectively. NSTAR Electric is a party to a five-year $450 million revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop NSTAR Electric's $450 million commercial paper program. There were no borrowings outstanding on the revolving credit facility as of March 31, 2017 or December 31, 2016.

Amounts outstanding under the commercial paper programs are included in Notes Payable for Eversource and NSTAR Electric and are classified in current liabilities on the balance sheets as all borrowings are outstanding for no more than 364 days at one time. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are included in Notes Payable to Eversource Parent and are classified in current liabilities on their respective balance sheets. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are eliminated in consolidation on Eversource's balance sheets.

Long-Term Debt Issuances: In March 2017, Eversource parent issued $300 million of 2.75 percent Series K Senior Notes due to mature in 2022. The proceeds, net of issuance costs, were used to repay short-term borrowings under the Eversource parent commercial paper program.

In March 2017, CL&P issued $300 million of 3.20 percent 2017 Series A First and Refunding Mortgage Bonds due to mature in 2027. The proceeds, net of issuance costs, were used to repay short-term borrowings.

Long-Term Debt Repayments: In March 2017, CL&P repaid at maturity the $150 million 5.375 percent 2007 Series A First and Refunding Mortgage Bonds, using short term borrowings.

Long-Term Debt Issuance Authorizations: On January 4, 2017, PURA approved CL&P's request for authorization to issue up to $1.325 billion in long-term debt through December 31, 2020. On March 30, 2017, the DPU approved NSTAR Electric's request for authorization to issue up to $700 million in long-term debt through December 31, 2018.