CONSOLIDATED STATEMENT OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating Activities:
Net Income	$ 100,755	$ 115,584
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Bad Debt Expense	3,657	4,947
Depreciation	80,839	73,951
Deferred Income Tax Expense (Benefit)	52,474	52,429
Pension, SERP, and PBOP Expense, Net of PBOP Contributions	42,268	34,163
Pension and PBOP Contributions	(98,910)	(5,932)
Regulatory (Underrecoveries)/Overrecoveries, Net	(28,352)	44,420
Amortization of Regulatory Assets/(Liabilities), Net	6,209	34,407
Amortization of Rate Reduction Bonds	18,347	17,282
Changes in Derivative Assets and Liabilities	(1,770)	(3,651)
Other Noncash Income (Expense)	(7,371)	(1,776)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	29,276	8,199
Inventory	30,108	42,990
Taxes Receivable/(Accrued)	11,758	18,312
Change in Accounts Payable	(190,232)	(29,278)
Other Current Assets and Liabilities	(40,240)	(33,281)
Net Cash Flows (Used in)/ Provided by Operating Activities	8,816	372,766
Investing Activities:
Investments in Property, Plant and Equipment	(304,294)	(236,689)
Proceeds from Sales of Marketable Securities	40,947	38,646
Purchases of Marketable Securities	(41,570)	(39,230)
Other Investing Activities	2,448	328
Net Cash Flows Used in Investing Activities	(302,469)	(236,945)
Financing Activities:
Cash Dividends on Common Stock	(52,104)	(48,588)
Cash Dividends on Preferred Stock	(1,390)	(1,390)
Increase/(Decrease) in Short-Term Debt	343,000	(78,000)
Issuance of Long-Term Debt	300,000	0
Retirements of Rate Reduction Bonds	(17,903)	(16,868)
Other Financing Activities	(1,130)	989
Net Cash Flows Provided by/(Used in) Financing Activities	570,473	(143,857)
Net Increase/(Decrease) in Cash	276,820	(8,036)
Cash - Beginning of Year	6,559	23,395
Cash - End of Year	283,379	15,359
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	53,985	64,337
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Bad Debt Expense	347	679
Depreciation	41,070	39,475
Deferred Income Tax Expense (Benefit)	32,460	28,592
Pension, SERP, and PBOP Expense, Net of PBOP Contributions	9,095	6,075
Regulatory (Underrecoveries)/Overrecoveries, Net	(39,726)	22,972
Amortization of Regulatory Assets/(Liabilities), Net	8,313	19,343
Other Noncash Income (Expense)	(6,746)	(20,129)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	28,685	16,187
Taxes Receivable/(Accrued)	16,551	57,078
Change in Accounts Payable	(146,676)	(14,135)
Other Current Assets and Liabilities	(44,484)	(15,511)
Net Cash Flows (Used in)/ Provided by Operating Activities	(47,126)	204,963
Investing Activities:
Investments in Property, Plant and Equipment	(108,842)	(106,829)
Other Investing Activities	1,139	(45)
Net Cash Flows Used in Investing Activities	(107,703)	(106,874)
Financing Activities:
Cash Dividends on Common Stock	(33,495)	(131,507)
Cash Dividends on Preferred Stock	(1,390)	(1,390)
Increase/(Decrease) in Short-Term Debt	244,000	10,000
Increase/(Decrease) in NU Money Pool Borrowings	(49,250)	18,950
Other Financing Activities	(1,200)	(92)
Net Cash Flows Provided by/(Used in) Financing Activities	158,665	(104,039)
Net Increase/(Decrease) in Cash	3,836	(5,950)
Cash - Beginning of Year	1	9,762
Cash - End of Year	3,837	3,812
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	21,262	27,464
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Bad Debt Expense	1,732	1,850
Depreciation	21,208	17,907
Deferred Income Tax Expense (Benefit)	8,908	3,672
Pension, SERP, and PBOP Expense, Net of PBOP Contributions	7,032	6,930
Pension and PBOP Contributions	(89,012)	(1,076)
Regulatory (Underrecoveries)/Overrecoveries, Net	911	(1,271)
Amortization of Regulatory Assets/(Liabilities), Net	(2,622)	15,567
Amortization of Rate Reduction Bonds	13,930	13,135
Other Noncash Income (Expense)	7,837	4,140
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	2,480	10,077
Inventory	9,361	16,043
Taxes Receivable/(Accrued)	10,138	18,971
Change in Accounts Payable	(16,073)	(2,160)
Other Current Assets and Liabilities	18,869	8,361
Net Cash Flows (Used in)/ Provided by Operating Activities	15,961	139,610
Investing Activities:
Investments in Property, Plant and Equipment	(67,059)	(57,718)
Decrease/(Increase) in NU Money Pool Lending	55,900	(16,100)
Other Investing Activities	963	369
Net Cash Flows Used in Investing Activities	(10,196)	(73,449)
Financing Activities:
Cash Dividends on Common Stock	(42,891)	(14,707)
Increase/(Decrease) in Short-Term Debt	45,000	(10,000)
Increase/(Decrease) in NU Money Pool Borrowings	7,900	(47,900)
Retirements of Rate Reduction Bonds	(13,463)	(12,697)
Capital Contributions from NU Parent	0	20,000
Other Financing Activities	(116)	(68)
Net Cash Flows Provided by/(Used in) Financing Activities	(3,570)	(65,372)
Net Increase/(Decrease) in Cash	2,195	789
Cash - Beginning of Year	56	2,559
Cash - End of Year	2,251	3,348
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	14,186	9,966
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Bad Debt Expense	739	1,337
Depreciation	7,697	6,338
Deferred Income Tax Expense (Benefit)	9,198	4,507
Pension, SERP, and PBOP Expense, Net of PBOP Contributions	1,766	1,096
Regulatory (Underrecoveries)/Overrecoveries, Net	(2,242)	7,620
Amortization of Regulatory Assets/(Liabilities), Net	121	(600)
Amortization of Rate Reduction Bonds	4,418	4,146
Other Noncash Income (Expense)	(1,810)	(1,370)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(2,274)	(2,384)
Taxes Receivable/(Accrued)	1,051	10,019
Change in Accounts Payable	(21,870)	(4,584)
Other Current Assets and Liabilities	(5,885)	(4,519)
Net Cash Flows (Used in)/ Provided by Operating Activities	5,095	31,572
Investing Activities:
Investments in Property, Plant and Equipment	(85,011)	(33,037)
Proceeds from Sales of Marketable Securities	31,579	32,414
Purchases of Marketable Securities	(31,680)	(32,510)
Decrease/(Increase) in NU Money Pool Lending	11,000	0
Other Investing Activities	(169)	(333)
Net Cash Flows Used in Investing Activities	(74,281)	(33,466)
Financing Activities:
Cash Dividends on Common Stock	(9,432)	(6,576)
Increase/(Decrease) in Short-Term Debt	65,000	10,000
Increase/(Decrease) in NU Money Pool Borrowings	18,200	3,000
Retirements of Rate Reduction Bonds	(4,440)	(4,170)
Other Financing Activities	(17)	(7)
Net Cash Flows Provided by/(Used in) Financing Activities	69,311	2,247
Net Increase/(Decrease) in Cash	125	353
Cash - Beginning of Year	1	1
Cash - End of Year	$ 126	$ 354