Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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SHORT-TERM AND LONG-TERM DEBT - Long-Term Debt Repayments (Details) - USD ($) $ in Thousands	1 Months Ended		9 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Sep. 30, 2016
Debt Instrument [Line Items]
Repayments of debt			$ 320,000	$ 200,000
The Connecticut Light And Power Company
Debt Instrument [Line Items]
Repayments of debt			250,000	0
Public Service Company Of New Hampshire
Debt Instrument [Line Items]
Repayments of debt			$ 70,000	$ 0
2007 Series A First and Refunding Mortgage Bonds \| Senior Notes \| The Connecticut Light And Power Company
Debt Instrument [Line Items]
Repayments of debt		$ 150,000
Interest rate stated percentage		5.375%
2007 Series C First and Refunding Mortgage Bonds \| Senior Notes \| The Connecticut Light And Power Company
Debt Instrument [Line Items]
Repayments of debt	$ 100,000
Interest rate stated percentage	5.75%		5.75%
2007 Series N First Mortgage Bonds \| Senior Notes \| Public Service Company Of New Hampshire
Debt Instrument [Line Items]
Repayments of debt	$ 70,000
Interest rate stated percentage	6.15%		6.15%
Series M First Mortgage Bonds \| Senior Notes \| NSTAR Gas Company
Debt Instrument [Line Items]
Repayments of debt	$ 25,000
Interest rate stated percentage	7.04%		7.04%