CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Income	$ 271,426	$ 261,338
Other Comprehensive (Loss)/Income, Net of Tax:
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	2,993	962
Qualified Cash Flow Hedging Instruments	724	534
Changes in Unrealized (Losses)/Gains on Marketable	(444)	1,645
Net OCI	3,273	3,141
Comprehensive Income Attributable to Noncontrolling Interests	(1,880)	(1,880)
Comprehensive Income Attributable to Common Shareholders	272,819	262,599
The Connecticut Light And Power Company
Net Income	98,568	90,208
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	52	111
Changes in Unrealized (Losses)/Gains on Marketable	(12)	56
Net OCI	40	167
Comprehensive Income Attributable to Common Shareholders	98,608	90,375
NSTAR Electric Company
Net Income	77,149	83,381
Other Comprehensive (Loss)/Income, Net of Tax:
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	1	(4)
Qualified Cash Flow Hedging Instruments	109	109
Changes in Unrealized (Losses)/Gains on Marketable	(4)	16
Net OCI	106	121
Comprehensive Income Attributable to Common Shareholders	77,255	83,502
Public Service Company Of New Hampshire
Net Income	35,093	34,312
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	290	291
Changes in Unrealized (Losses)/Gains on Marketable	(21)	97
Net OCI	269	388
Comprehensive Income Attributable to Common Shareholders	$ 35,362	$ 34,700