XML 102 R78.htm IDEA: XBRL DOCUMENT v3.10.0.1
FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption $ 155,570 $ 155,570
Rate Reduction Bonds 604,936 0
Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 155,600 155,600
Long-Term Debt 12,396,600 12,325,500
Rate Reduction Bonds 635,700  
Fair Value | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 156,400 160,800
Long-Term Debt 12,501,700 12,877,100
Rate Reduction Bonds 638,300  
The Connecticut Light and Power Company    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 116,200 116,200
The Connecticut Light and Power Company | Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 116,200 116,200
Long-Term Debt 3,253,300 3,059,100
Rate Reduction Bonds 0  
The Connecticut Light and Power Company | Fair Value | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 113,900 116,500
Long-Term Debt 3,473,300 3,430,500
Rate Reduction Bonds 0  
NSTAR Electric Company    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 43,000 43,000
NSTAR Electric Company | Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 43,000 43,000
Long-Term Debt 2,944,300 2,943,800
Rate Reduction Bonds 0  
NSTAR Electric Company | Fair Value | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 42,500 44,300
Long-Term Debt 3,019,900 3,156,500
Rate Reduction Bonds 0  
Public Service Company of New Hampshire    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Rate Reduction Bonds 604,936 0
Public Service Company of New Hampshire | Carrying Amount    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 0 0
Long-Term Debt 894,000 1,002,400
Rate Reduction Bonds 635,700  
Public Service Company of New Hampshire | Fair Value | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Preferred Stock Not Subject to Mandatory Redemption 0 0
Long-Term Debt 909,000 $ 1,038,200
Rate Reduction Bonds $ 638,300