UIL (UIL) Inactive 10-K20 Feb 142013 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2013	Feb. 14, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'UIL HOLDINGS CORP	'	'
Entity Central Index Key	'0001082510	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$1,914,519,791
Entity Common Stock, Shares Outstanding	'	56,462,507	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'

CONSOLIDATED_STATEMENT_OF_INCO

CONSOLIDATED STATEMENT OF INCOME (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENT OF INCOME [Abstract]	'	'	'
Operating Revenues	$1,618,716	$1,486,501	$1,570,094
Operation	'	'	'
Purchased power	139,135	154,546	180,149
Natural gas purchased	438,189	370,234	429,079
Operation and maintenance	384,029	356,277	381,814
Transmission wholesale	88,206	79,469	77,997
Depreciation and amortization (Note F)	189,856	181,348	167,462
Taxes - other than income taxes (Note F)	130,458	114,037	114,211
Regulatory disallowances	8,354	0	0
Total Operating Expenses	1,378,227	1,255,911	1,350,712
Operating Income	240,489	230,590	219,382
Other Income and (Deductions), net (Note F), (Note H)	20,633	25,246	26,932
Interest Charges, net	'	'	'
Interest on long-term debt	87,232	86,469	87,394
Other interest, net (Note F)	2,106	3,636	5,216
Interest Charges, gross	89,338	90,105	92,610
Amortization of debt expense and redemption premiums	2,431	2,437	2,775
Total Interest Charges, net	91,769	92,542	95,385
Income from Equity Investments	15,272	15,273	11,282
Income Before Income Taxes	184,625	178,567	162,211
Income Taxes (Note E)	69,308	74,866	62,501
Net Income (Loss)	115,317	103,701	99,710
Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	52	64	54
Net Income attributable to UIL Holdings	$115,265	$103,637	$99,656
Average Number of Common Shares Outstanding - Basic (in shares)	52,415	50,831	50,609
Average Number of Common Shares Outstanding - Diluted (in shares)	52,711	51,108	50,926
Earnings Per Share of Common Stock - Basic (Note A) (in dollars per share)	$2.20	$2.04	$1.96
Earnings Per Share of Common Stock - Diluted (Note A) (in dollars per share)	$2.18	$2.02	$1.95
Cash Dividends Declared per share of Common Stock (in dollars per share)	$1.73	$1.73	$1.73

CONSOLIDATED_STATEMENT_OF_COMP

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME [Abstract]	'	'	'
Net Income	$115,317	$103,701	$99,710
Other Comprehensive Income (Loss), net of deferred income taxes [Abstract]	'	'	'
Changes in unrealized gains (losses) related to pension and other post-retirement benefit plans	1,008	-90	-576
Other	-24	16	35
Total other comprehensive income (loss), net of deferred income taxes	984	-74	-541
Comprehensive income	116,301	103,627	99,169
Less:	'	'	'
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	52	64	54
Comprehensive Income attributable to UIL Holdings	$116,249	$103,563	$99,115

CONSOLIDATED_STATEMENT_OF_CASH

CONSOLIDATED STATEMENT OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Cash Flows From Operating Activities	'		'		'
Net income	$115,317		$103,701		$99,710
Adjustments to reconcile net income to net cash provided by operating activities:	'		'		'
Depreciation and amortization	192,287		183,785		170,237
Deferred income taxes	71,095		68,121		83,273
Allowance for funds used during construction (AFUDC) - equity	-10,811		-7,480		-10,539
Stock-based compensation expense (Note A)	5,283		4,907		5,286
Pension expense	48,798		39,906		39,028
Undistributed (earnings) losses in equity investments	-15,304		-15,440		-11,702
Regulatory disallowances	8,354		0		0
Other regulatory activity, net	10,945		-16,102		-85,255
Other non-cash items, net	-757		-7,049		16,168
Changes in:	'		'		'
Accounts receivable, net	-9,711		-51,301		34,654
Unbilled revenues	-9,058		-11,999		9,693
Natural gas in storage	4,850		26,748		-3,436
Cash distribution received from GenConn	15,321		19,672		7,977
Accounts payable	-12,094		-20,221		4,446
Interest accrued	-494		900		-1,341
Taxes accrued/refundable, net	-1,302		60,614		-41,366
Accrued liabilities	-2,504		16,271		-2,528
Accrued pension	-74,666		-59,317		-77,005
Increase (decrease) in Other employee related liabilities	-8,052		-3,673		-5,534
Other assets	-2,636		6,811		2,750
Other liabilities	347		-4,913		-11,654
Total Adjustments	209,891		230,240		123,152
Net Cash provided by Operating Activities	325,208		333,941		222,862
Cash Flows from Investing Activities	'		'		'
Acquisition of Gas companies, net of cash acquired	0		0		11,211
Related party note receivable	0		0		-1,050
Plant expenditures including AFUDC debt	-305,178	[1]	-288,633	[1]	-328,079	[1]
Investment in GenConn	0		0		-2,000
Cash distributions from GenConn	6,494		1,872		0
Changes in restricted cash	759		3,717		-4,123
Deposits in New England East West Solution (NEEWS) (Note C)	-1,636		-24,059		-2,393
Other	360		844		401
Net Cash (used in) Investing Activities	-299,201		-306,259		-326,033
Cash Flows from Financing Activities	'		'		'
Issuance of common stock	206,516		1,943		200
Issuances of long-term debt	135,000		203,500		51,050
Payments on long-term debt	-41,455		-109,955		-146,573
Line of credit borrowings (repayments), net	-187,000		-48,000		228,000
Payment of common stock dividend	-87,602		-87,490		-87,274
Other	-170		-822		-1,514
Net Cash provided by (used in) Financing Activities	25,289		-40,824		43,889
Unrestricted Cash and Temporary Cash Investments:	'		'		'
Net change for the period	51,296		-13,142		-59,282
Balance at beginning of period	17,857		30,999		90,281
Balance at end of period	69,153		17,857		30,999
Cash paid during the period for:	'		'		'
Interest (net of amount capitalized)	83,259		81,658		83,365
Income taxes	5,735		4,750		11,475
Non-cash investing activity:	'		'		'
Plant expenditures included in ending accounts payable	33,145		47,475		45,046
Related party note receivable (Note H)	0		0		62,833
Equity investment in Related Party (Note H)	0		0		-62,833
Plant expenditures funded by deposits in NEEWS	-18,469		-6,346		0
Deposits in New England East West Solution (NEEWS)	$18,469		$6,346		$0

[1]	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.

CONSOLIDATED_BALANCE_SHEET

CONSOLIDATED BALANCE SHEET (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Current Assets	'		'
Unrestricted cash and temporary cash investments	$69,153		$17,857
Restricted cash	2,046		2,805
Accounts receivable less allowance of $12,021 and $11,867, respectively	245,252		238,986
Unbilled revenues	93,050		83,956
Current regulatory assets (Note A)	332,391		120,935
Natural gas in storage, at average cost	79,917		84,768
Deferred income taxes	21,742		41,605
Refundable taxes	8,244		1,686
Current portion of derivative assets (Note A)	9,098		12,671
Prepayments	14,989		11,907
Other	12,122		11,507
Total Current Assets	888,004		628,683
Other investments	'		'
Equity investment in GenConn (Note A)	118,241		124,799
Other	26,348		23,931
Total Other investments	144,589		148,730
Net Property, Plant and Equipment (Note A)	3,068,680		2,847,151
Regulatory Assets (Note A)	703,739		1,014,515
Deferred Charges and Other Assets	'		'
Unamortized debt issuance expenses	15,518		16,625
Other long-term receivable	1,496		1,501
Derivative assets (Note A)	44,349		67,167
Goodwill	266,205		266,205
Other	11,640		28,587
Total Deferred Charges and Other Assets	339,208		380,085
Total Assets	5,144,220		5,019,164	[1]
Current Liabilities	'		'
Line of credit borrowings	0		187,000
Current portion of long-term debt	11,834	[2]	48,296	[2]
Accounts payable	164,416		189,991
Dividends payable	24,392		21,887
Accrued liabilities	78,125		85,132
Current regulatory liabilities (Note A)	261,729		21,284
Taxes accrued	23,490		18,235
Interest accrued	21,933		22,427
Current portion of derivative liabilities (Note A)	26,904		30,804
Total Current Liabilities	612,823		625,056
Deferred Income Taxes (future tax liabilities owed to taxing authorities)	540,542		462,940
Regulatory Liabilities (Note A)	445,092		504,953
Other Noncurrent Liabilities	'		'
Pension accrued	170,853		325,547
Connecticut Yankee contract obligation (Note J)	0		11,129
Other post-retirement benefits accrued	78,539		98,147
Derivative liabilities (Note A)	169,327		224,639
Other	49,047		49,506
Total Other Noncurrent Liabilities	467,766		708,968
Commitments and Contingencies (Note J)	'		'
Capitalization (Note B)	'		'
Long-term debt, net of unamortized discount and premium	1,723,842		1,600,354
Preferred Stock, not subject to mandatory redemption	340		340
Common Stock Equity	'		'
Common stock	1,145,950		936,702
Paid-in capital	22,272		20,400
Retained earnings	185,058		159,900
Accumulated other comprehensive loss	535		-449
Net Common Stock Equity	1,353,815		1,116,553
Total Capitalization	3,077,997		2,717,247
Total Liabilities and Capitalization	$5,144,220		$5,019,164

[1]	Includes $266.8 million of goodwill in the Gas Distribution segment as of December 31, 2012 and 2011.
[2]	Includes the current portion of unamortized premium.

CONSOLIDATED_BALANCE_SHEET_Par

CONSOLIDATED BALANCE SHEET (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current Assets	'	'
Allowance for doubtful accounts receivable	$12,021	$11,867

Consolidated_Statement_of_Chan

Consolidated Statement of Changes in Shareholders' Equity (USD $)		Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
In Thousands, except Share data		Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2010		$927,494	$17,026	$131,456	$166	$1,076,142
Balance (in shares) at Dec. 31, 2010	[1]	50,505,451,000	'	'	'	'
Net income		'	'	99,710	'	99,710
Cash dividends on common stock		'	'	-87,320	'	-87,320
Preferred stock dividends of subsidiary, noncontrolling interests		'	'	-54	'	-54
Issuance of common stock - no par value		3,659	'	'	'	3,659
Issuance of common stock - no par value (in shares)	[1]	140,039,000	'	'	'	'
Stock based compensation		'	2,765	'	'	2,765
Other comprehensive income (loss), net		'	'	'	-541	-541
Balance at Dec. 31, 2011		931,153	19,791	143,792	-375	1,094,361
Balance (in shares) at Dec. 31, 2011	[1]	50,645,490,000	'	'	'	'
Net income		'	'	103,701	'	103,701
Cash dividends on common stock		'	'	-87,529	'	-87,529
Preferred stock dividends of subsidiary, noncontrolling interests		'	'	-64	'	-64
Issuance of common stock - no par value		5,549	'	'	'	5,549
Issuance of common stock - no par value (in shares)	[1]	229,093,000	'	'	'	'
Stock based compensation		'	609	'	'	609
Other comprehensive income (loss), net		'	'	'	-74	-74
Balance at Dec. 31, 2012		936,702	20,400	159,900	-449	1,116,553
Balance (in shares) at Dec. 31, 2012	[1]	50,874,583,000	'	'	'	'
Net income		'	'	115,317	'	115,317
Cash dividends on common stock		'	'	-90,107	'	-90,107
Preferred stock dividends of subsidiary, noncontrolling interests		'	'	-52	'	-52
Issuance of common stock - no par value		209,248	'	'	'	209,248
Issuance of common stock - no par value (in shares)	[1]	5,879,260,000	'	'	'	'
Stock based compensation		'	1,872	'	'	1,872
Other comprehensive income (loss), net		'	'	'	984	984
Balance at Dec. 31, 2013		$1,145,950	$22,272	$185,058	$535	$1,353,815
Balance (in shares) at Dec. 31, 2013	[1]	56,753,843,000	'	'	'	'

[1]	There were 125,000,000 shares authorized in 2012 and 2011

Consolidated_Statement_of_Chan1

Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statement of Changes in Shareholders' Equity [Abstract]	'	'	'
Cash dividends on common stock (in dollars per share)	$1.73	$1.73	$1.73
Common stock issued (in shares)	5,797,393	119,627	102,404
Other comprehensive income (loss), net of deferred income taxes	$656	($49)	($361)
Common stock, shares authorized (in shares)	125,000,000	125,000,000	'

STATEMENT_OF_ACCOUNTING_POLICI

STATEMENT OF ACCOUNTING POLICIES	12 Months Ended
STATEMENT OF ACCOUNTING POLICIES	Dec. 31, 2013
STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
STATEMENT OF ACCOUNTING POLICIES	'
	(A) STATEMENT OF ACCOUNTING POLICIES

	UIL Holdings is headquartered in New Haven, Connecticut, where its senior management maintains offices and is responsible for overall planning, operating and financial functions. The primary business of UIL Holdings is ownership of its operating regulated utility businesses. The utility businesses consist of the electric distribution and transmission operations of The United Illuminating Company (UI) and the natural gas transportation, distribution and sales operations of The Southern Connecticut Gas Company (SCG), Connecticut Natural Gas Corporation (CNG) and The Berkshire Gas Company (Berkshire, and together with SCG and CNG, the Gas Companies).

	UI is also a party to a joint venture with certain affiliates of NRG Energy, Inc. (NRG affiliates) pursuant to which UI holds 50% of the membership interests in GCE Holding LLC, whose wholly owned subsidiary, GenConn Energy LLC (collectively with GCE Holding LLC, GenConn) operates peaking generation plants in Devon, Connecticut (GenConn Devon) and Middletown, Connecticut (GenConn Middletown).

	Accounting Records

	The accounting records of UIL Holdings are maintained in conformity with generally accepted accounting principles in the United States of America (GAAP).

	The accounting records for UI and the Gas Companies are also maintained in accordance with the uniform systems of accounts prescribed by the Federal Energy Regulatory Commission (FERC), the Connecticut Public Utilities Regulatory Authority (PURA), and the Massachusetts Department of Public Utilities (DPU), as applicable.

	Basis of Presentation

	The financial statements of UIL Holdings are prepared on a consolidated basis and therefore include the accounts of UIL Holdings’ majority-owned subsidiaries noted above. Intercompany accounts and transactions have been eliminated in consolidation.

	The preparation of financial statements in conformity with GAAP requires management to use estimates and assumptions that affect (1) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and (2) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

	The Company has revised its previously issued annual financial statements to correct an error in the 2012 Consolidated Balance Sheet. The effect of this revision is a $59.8 million adjustment increasing net property, plant and equipment and increasing non-current regulatory liabilities in the Consolidated Balance Sheet as of December 31, 2012. The Company has also revised the 2012 Consolidated Balance sheet for an adjustment, the effect of which is a $13.1 million adjustment increasing accounts payable and decreasing accrued liabilities in the Consolidated Balance Sheet as of December 31, 2012. These adjustments are not considered to be material individually or in the aggregate to previously issued financial statements. These adjustments did not have an impact on the Consolidated Statements of Income, Comprehensive Income, Cash Flows and Changes in Stockholders' Equity. Additionally certain immaterial amounts that were reported as such in the Consolidated Financial Statements in previous periods have been reclassified to conform to the current presentation.

	Allowance for Funds Used During Construction

	In accordance with the uniform systems of accounts, the Company capitalizes allowance for funds used during construction (AFUDC) , which represents the approximate cost of debt and equity capital devoted to plant under construction. The portion of the allowance applicable to borrowed funds and the allowance applicable to equity funds are presented as other income in the Consolidated Statement of Income. Although the allowance does not represent current cash income, it has been recoverable under the ratemaking process over the service lives of the related properties. Weighted-average AFUDC rates for 2013, 2012 and 2011 were 9.63%, 5.61% and 5.75%, respectively.

	Asset Retirement Obligations

	The fair value of the liability for an asset retirement obligation (ARO) and/or a conditional ARO is recorded in the period in which it is incurred and the cost is capitalized by increasing the carrying amount of the related long-lived asset. The liability is adjusted to its present value periodically over time, and the capitalized cost is depreciated over the useful life of the related asset. Upon settlement, the obligation is settled either at its recorded amount or a gain or a loss is incurred.

	Any timing differences between rate recovery and depreciation expense are deferred as either a regulatory asset or a regulatory liability.

	The term conditional ARO refers to an entity's legal obligation to perform an asset retirement activity in which the timing and/or method of settlement are conditional on a future event that may or may not be within the control of the entity. If an entity has sufficient information to reasonably estimate the fair value of the liability for a conditional ARO, it must recognize that liability at the time the liability is incurred.

	As of December 31, 2013 and 2012, UIL Holdings’ ARO, including estimated conditional AROs, was $18.5 million and $18.3 million, respectively, and consisted primarily of obligations related to the removal or retirement of asbestos, polychlorinated biphenyl (PCB)-contaminated equipment, gas pipeline and cast iron gas mains. The long-lived assets associated with the AROs are gas storage property, distribution property and other property. UIL Holdings’ ARO is carried on the balance sheet as other long-term liabilities.

	ARO activity for 2013 and 2012 is as follows:

			2013				2012
			(In Thousands)
	Balance as of December 31		$	18,289			$	18,058
	Liabilities incurred during the year			-				-
	Liabilities settled during the year			(740	)			(718	)
	Accretion			961				949
	Balance as of December 31		$	18,510			$	18,289

	Cash and Temporary Cash Investments

	UIL Holdings considers all of its highly liquid debt instruments with an original maturity of three months or less at the date of purchase to be cash and temporary cash investments.

	Depreciation

	Provisions for depreciation on utility plant for book purposes are computed on a straight‑line basis, using estimated service lives. For utility plant other than software, service lives are determined by independent engineers and subject to review and approval by PURA and DPU. Software service life is based upon management’s estimate of useful life. The aggregate annual provisions for depreciation for the years 2013, 2012 and 2011 were approximately 3.4%, 3.5%, and 3.3%, respectively, of the original cost of depreciable property.

	Derivatives

	UIL Holdings’ regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives. The values of the gross derivative assets and liabilities as of December 31, 2013 and 2012 were as follows:

			December 31,				December 31,
			2013				2012
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,098			$	12,671
	Deferred Charges and Other Assets		$	44,349			$	67,167

Gross derivative liabilties:
Current Liabilities		$	26,976			$	30,804
Noncurrent Liabilities		$	169,327			$	224,639

Contracts for Differences (CfDs)
Pursuant to Connecticut’s 2005 Energy Independence Act, the Connecticut Public Utilities Regulatory Authority (PURA) solicited bids to create new or incremental capacity resources in order to reduce federally mandated congestion charges, and selected four new capacity resources. To facilitate the transactions between the selected capacity resources and Connecticut electric customers, and provide the commitment necessary for owners of these resources to obtain necessary financing, PURA required that UI and The Connecticut Light and Power Company (CL&P) execute long-term contracts with the selected resources. In August 2007, PURA approved four CfDs, each of which specifies a capacity quantity and a monthly settlement that reflects the difference between a forward market price and the contract price. UI executed two of the contracts and CL&P executed the other two contracts. The costs or benefits of each contract will be paid by or allocated to customers and will be subject to a cost-sharing agreement whereby approximately 20% of the cost or benefit is borne by or allocated to UI customers and approximately 80% is borne by or allocated to CL&P customers.
PURA has determined that costs associated with these CfDs will be recoverable by UI and CL&P, and in accordance with ASC 980 “Regulated Operations,” UI has deferred recognition of costs (a regulatory asset) or obligations (a regulatory liability). The CfDs are marked-to-market in accordance with ASC 815 “Derivatives and Hedging.” For those CfDs signed by CL&P, UI records its approximate 20% portion pursuant to the cost-sharing agreement noted above. As of December 31, 2013, UI has recorded a gross derivative asset of $53.4 million, a regulatory asset of $142.7 million, and a gross derivative liability of $196.2 million ($129.4 million of which is related to UI’s portion of CL&P’s derivative liabilities). See Note (K) “Fair Value of Financial Instruments” for additional CfD information.
The unrealized gains and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for years ended December 31, 2013 and 2012 were as follows:

		Year Ended
		December 31,
		2013				2012
		(In Thousands)

Regulatory Assets - Derivative liabilities		$	(33,819	)		$	(7,500	)

Regulatory Liabilities - Derivative assets		$	-			$	12

The increase in unrealized losses in the year ended December 31, 2013 compared to 2012 is due to increases in forward pricing.

Weather Insurance Contracts

On an annual basis, the Gas Companies each assess the need for weather insurance contracts for the upcoming heating season in order to provide financial protection from significant weather fluctuations. According to the terms of such contracts, if temperatures are warmer than normal at a prescribed level for the contract period, a payment is received by the gas company; in addition, under certain of the contracts, if temperatures are colder than normal at a prescribed level for the contract period, the gas company is required to make a payment. The premiums paid are amortized over the terms of the contracts. The intrinsic value of the contracts is carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).

In October of 2013, CNG entered into a weather insurance contract for the period of November 1, 2013 through December 31, 2013. If temperatures were warmer than normal, CNG would receive a payment, up to a maximum of $1.5 million; however, if temperatures were colder than normal, CNG would make a payment of up to a maximum of $1 million. As a result of PURA’s approval for a decoupling mechanism which went into effect on January 10, 2014, the contract did not extend into the 2014 portion of the heating season. The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $0.1 million at December 31, 2013, and was subsequently paid.

In October 2013, Berkshire entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014. If temperatures are warmer than normal, Berkshire will receive a payment, up to a maximum of $1 million; however, if temperatures are colder than normal, Berkshire will make a payment of up to a maximum of $0.2 million. The contract had no value at December 31, 2013 since the variation from normal weather through December 31, 2013 did not reach the prescribed level stated in the contract.

In September 2013, SCG entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014. If temperatures are warmer than normal, SCG will receive a payment, up to a maximum of $3 million; however, if temperatures are colder than normal, SCG will make a payment of up to a maximum of $2 million. The contract had no value at December 31, 2013 since the variation from normal weather through December 31, 2013 did not reach the prescribed level stated in the contract.

In October 2012, SCG and CNG each entered into weather insurance contracts for the winter period of November 1, 2012 through April 30, 2013. If temperatures were warmer than normal, SCG and CNG each would have received a payment, up to a maximum of $3 million; however, if temperatures were colder than normal, SCG and CNG each would have made a payment of up to a maximum of $2 million. Upon the expiration of their respective contracts, SCG and CNG neither received nor made a payment since the variation from normal weather during the contract period did not reach the prescribed level stated in the contracts.

In November 2011, Berkshire entered into a weather insurance contract for calendar year 2012. According to the terms of the contract, because temperatures were warmer than normal for the contract period, Berkshire received a payment of $1 million on January 8, 2013. The premiums paid were amortized over the term of the contract. The intrinsic value of the contract, $1 million at December 31, 2012, was carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).

Earnings per Share

The following table presents a reconciliation of the basic and diluted earnings per share calculations for the years 2013, 2012 and 2011:


		Year Ended December 31,
		2013				2012				2011
		(In Thousands, except per share amounts)

Numerator:
Net income attributable to UIL Holdings		$	115,265			$	103,637			$	99,656
Less: Net income allocated to unvested units			117				184				210
Net income attributable to common shareholders		$	115,148			$	103,453			$	99,446

Denominator:
Basic average number of shares outstanding			52,415				50,831				50,609
Effect of dilutive securities			296				277				317
Diluted average number of shares outstanding			52,711				51,108				50,926

Earnings per share:
Basic		$	2.2			$	2.04			$	1.96
Diluted		$	2.18			$	2.02			$	1.95

All outstanding options to purchase shares of common stock during 2013 and 2012 were included in the computation of diluted earnings per share because the options’ exercise prices were lower than the average market price of the common shares during such period. Options to purchase 89,336 shares of common stock were outstanding during 2011 but were not included in the computation of diluted earnings per share because the options’ exercise prices were greater than the average market price of the common shares during such period.

Equity Investments

UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut. UI’s investment in GenConn is being accounted for as an equity investment, the carrying value of which was $118.2 million and $124.8 million as of December 31, 2013 and 2012, respectively. As of December 31, 2013, there were approximately $0.1 million of undistributed earnings from UI’s equity investment in GenConn.

UI’s pre-tax income from its equity investment in GenConn was $15.3 million, $15.3 million and $11.3 million for the years ended December 31, 2013, 2012 and 2011, respectively.

Cash distributions from GenConn are reflected as either distributions of earnings or as returns of capital in the operating and investing sections of the Consolidated Statement of Cash Flows, respectively. During the years ended December 31, 2013, 2012 and 2011, UI received cash distributions from GenConn of approximately $21.8 million, $21.5 million and $8.0 million.

Goodwill

UIL Holdings may be required to recognize an impairment of goodwill in the future due to market conditions or other factors related to its results of operations and performance. Those market events could include a decline in the forecasted results in the company business plan, significant adverse rate case results, changes in capital investment budgets or changes in interest rates that could impair the fair value of a reporting unit. Recognition of impairments of a significant portion of goodwill would negatively affect reported results of operations and total capitalization, the effect of which could be material and could make it more difficult to maintain credit ratings, secure financing on attractive terms, maintain compliance with debt covenants and meet expectations of regulators.

A goodwill impairment test is performed each year and the test will be updated between annual tests if events or circumstances occur that may reduce the fair value of a reporting unit below its carrying value. The annual analysis of the potential impairment of goodwill is a two-step process. Step one of the impairment test consists of comparing the fair values of reporting units with their aggregate carrying values, including goodwill. The estimated fair values for the reporting units are determined by using the income approach and the market approach methodologies.

The income approach is based on discounted cash flows which are derived from internal forecasts and economic expectations. Key assumptions used to determine fair value under the income approach include the cash flow period, terminal values based on a terminal growth rate, and the discount rate. The discount rate represents the estimated cost of debt and equity financing weighted by the percentage of debt and equity in a company's target capital structure.

The market approach utilizes the guideline company method, which calculates valuation multiples based on operating and valuation metrics from publicly traded guideline companies in the regulated natural gas distribution industry. Multiples derived from the guideline companies provide an indication of how much a knowledgeable investor in the marketplace would be willing to pay for an investment in a similar company. These multiples are then applied to the appropriate operating metric to determine indications of fair value.

If the carrying amount of a reporting unit exceeds the reporting unit’s fair value, step two must be performed to determine the amount, if any, of the goodwill impairment loss. If the carrying amount is less than fair value, further testing of goodwill impairment is not performed.

Step two of the goodwill impairment test consists of comparing the implied fair value of the reporting unit’s goodwill against the carrying value of the goodwill. Determining the implied fair value of goodwill requires the valuation of a reporting unit’s identifiable tangible and intangible assets and liabilities as if the reporting unit had been acquired in a business combination on the testing date. The difference between the fair value of the entire reporting unit as determined in step one and the net fair value of all identifiable assets and liabilities represents the implied fair value of goodwill. A goodwill impairment charge, if any, would be the difference between the carrying amount of goodwill and the implied fair value of goodwill upon the completion of step two.

As of October 1, 2013, the fair values of UIL Holdings’ applicable reporting units exceeded their carrying values and therefore no impairment was recognized. No events or circumstances occurred subsequent to October 1, 2013 that would make it more likely than not that the fair value of the reporting units fell below their respective carrying values.

Impairment of Long‑Lived Assets and Investments

ASC 360 “Property, Plant, and Equipment” requires the recognition of impairment losses on long‑lived assets when the book value of an asset exceeds the sum of the expected future undiscounted cash flows that result from the use of the asset and its eventual disposition. If impairment arises, then the amount of any impairment is measured based on discounted cash flows or estimated fair value.

ASC 360 also requires that rate‑regulated companies recognize an impairment loss when a regulator excludes all or part of a cost from rates, even if the regulator allows the company to earn a return on the remaining costs allowed. Under this standard, the probability of recovery and the recognition of regulatory assets under the criteria of ASC 980 must be assessed on an ongoing basis. As discussed in the description of ASC 980 in this Note (A) under “Regulatory Accounting,” determination that certain regulatory assets no longer qualify for accounting as such could have a material impact on the financial condition of UI, the Gas Companies and UIL Holdings. As a result of UI’s 2013 distribution rate proceeding, a portion of UI’s deferred storm costs and capital costs related to UI’s recently constructed administrative and operations buildings were written off. See – Note (C), Regulatory Proceedings, Electric Distribution and Transmission – Rates, for additional information.

ASC 323 “Investments” requires that a loss in the value of an investment that is other than a temporary decline should be recognized. In accordance with ASC 323, UIL Holdings reviews its investments accounted for by the equity method for impairment by identifying and measuring losses in the value based upon a comparison of fair value to carrying value. At December 31, 2013, UIL Holdings did not have any equity investments that were impaired under this standard.

Income Taxes

In accordance with ASC 740 “Income Taxes,” UIL Holdings has provided deferred taxes for all temporary book‑tax differences using the liability method. The liability method requires that deferred tax balances be adjusted to reflect enacted future tax rates that are anticipated to be in effect when the temporary differences reverse. In accordance with generally accepted accounting principles for regulated industries, UIL Holdings’ regulated subsidiaries have established a regulatory asset for the net revenue requirements to be recovered from customers for the related future tax expense associated with certain of these temporary differences. For ratemaking purposes, UIL Holdings’ regulated subsidiaries normalize all investment tax credits (ITCs) related to recoverable plant investments.

Under ASC 740, UIL Holdings may recognize the tax benefit of an uncertain tax position only if management believes it is more likely than not that the tax position will be sustained on examination by the taxing authority based upon the technical merits of the position. The tax benefits recognized in the financial statements from such a position should be measured based upon the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. UIL Holdings’ policy is to recognize interest accrued and penalties associated with uncertain tax positions as a component of operating expense. See – Note (E), Income Taxes for additional information.

UIL Holdings files a consolidated federal tax return which includes all of the activities of its subsidiaries. Each subsidiary company is treated as a member of the consolidated group and each subsidiary company’s current and deferred tax expense or benefit is calculated based on the separate return method.

Pension and Other Postretirement Benefits

UIL Holdings accounts for pension plan costs and other postretirement benefits, consisting principally of health and life insurance, in accordance with the provisions of ASC 715 “Compensation - Retirement Benefits.” See – Note (G), Pension and Other Benefits.

Property, Plant and Equipment

The cost of additions to property, plant and equipment and the cost of renewals and betterments are capitalized. Cost consists of labor, materials, services and certain indirect construction costs, including AFUDC. The costs of current repairs, major maintenance projects and minor replacements are charged to appropriate operating expense accounts as incurred. The original cost of utility property, plant and equipment retired or otherwise disposed of and the cost of removal, less salvage, are charged to the accumulated provision for depreciation.

UI and the Gas Companies accrue for estimated costs of removal for certain of their plant-in-service. Such removal costs are included in the approved rates used to depreciate these assets. At the end of the service life of the applicable assets, the accumulated depreciation in excess of the historical cost of the asset provides for the estimated cost of removal. In accordance with ASC 980 “Regulated Operations,” the accrued costs of removal have been recorded as a regulatory liability.

UIL Holdings’ property, plant and equipment as of December 31, 2013 and 2012 were comprised as follows:


		2013				2012
		(In Thousands)

Electric distribution plant		$	979,526			$	860,096
Electric transmission plant			630,834				577,669
Gas distribution plant			1,444,837				1,386,288
Software			144,494				136,219
Building and improvements			235,002				220,821
Land			64,848				64,421
Other plant			192,219				184,061
Total property, plant & equipment			3,691,760				3,429,575
Less accumulated depreciation			944,399				893,764
			2,747,361				2,535,811
Construction work in progress			321,319				311,340
Net property, plant & equipment		$	3,068,680			$	2,847,151

Regulatory Accounting

Generally accepted accounting principles for regulated entities in the United States of America allow UIL Holdings’ regulated subsidiaries to give accounting recognition to the actions of regulatory authorities in accordance with the provisions of Accounting Standards Codification (ASC) 980 “Regulated Operations.” In accordance with ASC 980, UIL Holdings’ regulated utilities have deferred recognition of costs (a regulatory asset) or have recognized obligations (a regulatory liability) if it is probable that such costs will be recovered or obligations relieved in the future through the ratemaking process. UIL Holdings’ regulated utilities are allowed to recover all such deferred costs through its regulated rates. See Note (C), “Regulatory Proceedings,” for a discussion of the recovery of certain deferred costs, as well as a discussion of the regulatory decisions that provide for such recovery.

UI also has obligations under long‑term power contracts, the recovery of which is subject to regulation. If UIL Holdings’ regulated utilities, or a portion of their assets or operations, were to cease meeting the criteria for application of these accounting rules, accounting standards for businesses in general would become applicable and immediate recognition of any previously deferred costs would be required in the year in which such criteria are no longer met (if such deferred costs are not recoverable in the portion of the business that continues to meet the criteria for application of ASC 980). UIL Holdings expects its regulated utilities to continue to meet the criteria for application of ASC 980 for the foreseeable future. If a change in accounting were to occur, it could have a material adverse effect on the earnings and retained earnings of the applicable regulated utility and UIL Holdings in that year and could also have a material adverse effect on the ongoing financial condition of the applicable regulated utility and UIL Holdings.

Unless otherwise stated below, all of UIL Holdings’ regulatory assets earn a return. UIL Holdings’ regulatory assets and liabilities as of December 31, 2013 and 2012 included the following:

	Remaining		December 31,				December 31,
	Period		2013				2012
			(In Thousands)
Regulatory Assets:
Nuclear plant investments – above market	(a)		$	238,868			$	252,498
Connecticut Yankee	Not applicable			-				11,129
Unamortized redemption costs	8 to 20 years			11,301				12,103
Pension and other post-retirement benefit plans	(b)			316,076				458,019
Environmental remediation costs	3 years			14,953				14,772
Hardship programs	(c)			25,019				29,852
Debt premium	1 to 24 years			34,178				41,016
Deferred purchased gas	(d)			2,556				12,444
Income taxes due principally to book-tax differences	(m)			149,015				-
Deferred income taxes	(e)			861				-
Unfunded future income taxes	(e)			31,656				17,319
Contracts for differences	(f)			142,743				176,597
Excess generation service charge	(g)			6,909				8,864
Deferred transmission expense	(h)			9,615				21,379
Storm Costs	(i)			14,752				52,009
Other	(j)			37,628				27,449
Total regulatory assets				1,036,130				1,135,450
Less current portion of regulatory assets				332,391				120,935
Regulatory Assets, Net			$	703,739			$	1,014,515

Regulatory Liabilities:
Accumulated deferred investment tax credits	30 years		$	4,465			$	4,612
Income taxes due principally to book-tax differences	(m)			200,673				41,928
Deferred gain on sale of property	(a)			37,933				37,933
Middletown/Norwalk local transmission network service collections	36 years			21,402				21,975
Pension and other post-retirement benefit plans	6 years			27,686				15,016
Deferred income taxes	(e)			43,421				41,816
Asset retirement obligation	(k)			5,593				4,995
Low income programs	(l)			25,300				17,651
Asset removal costs	(j)			319,530				303,651
Other	(j)			20,818				36,660
Total regulatory liabilities				706,821				526,237
Less current portion of regulatory liabilities				261,729				21,284
Regulatory Liabilities, Net			$	445,092			$	504,953

a) Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet as of December 31, 2013.
(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See “-Contracts for Differences” discussion above for additional information.
(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($11.6 million) and certain other amounts that are not currently earning a return. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the decoupling recovery period.
(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
(l) Various hardship and payment plan programs approved for recovery.
(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA. In prior periods, these amounts were presented on a net basis in long-term regulatory liabilities. In the current period, due to the end of the CTA charge, the CTA regulatory liabilities have been reclassified to current regulatory liabilities and the regulatory assets not related to the CTA have been reclassified to long-term regulatory assets.

Restricted Cash

UIL Holdings’ restricted cash at December 31, 2013 and 2012 totaled $2.0 million and $2.8 million, respectively, which primarily relates to electric distribution and transmission capital projects, which have been withheld by UI and will remain in place until the verification of fulfillment of contractor obligations.

Revenues

Regulated utility revenues are based on authorized rates applied to each customer. These retail rates are approved by regulatory bodies and can be changed only through formal proceedings.

UI utilizes a customer accounting software package integrated with the network meter reading system to estimate unbilled revenue on a customer-by-customer basis, utilizing actual daily meter readings at the end of each month to calculate consumption and pricing for each customer. A significant portion of utility retail kilowatt-hour consumption is read through the network meter reading system. For those customers still requiring manual meter readings, consumption is estimated based upon historical usage and actual pricing for each customer.

The Gas Companies’ unbilled revenues represent estimates of receivables for products and services provided but not yet billed. The estimates are determined based on various assumptions, such as current month energy load requirements, billing rates by customer classification and weather.

Stock-Based Compensation

Certain members of management have the opportunity to earn a pre-determined number of performance shares, the number of which is predicated upon the achievement of various pre-defined performance measures over a three-year period. These performance shares are issued under the UIL Holdings 2008 Stock and Incentive Compensation Plan (2008 Stock Plan). Each award of performance shares vests at the end of a three-year cycle with the actual issuance of UIL Holdings’ common stock in respect of such performance shares following the end of each three-year cycle. A new three-year cycle begins in January of each year.

UIL Holdings records compensation expense for these performance shares ratably over the three-year period, except in the case of retirement-eligible employees, for whom compensation expense is immediately recognized in accordance with ASC 718 “Compensation-Stock Compensation,” based on the value of the expected payout at the end of each year relative to the performance measures achieved.

Pursuant to the 2008 Stock Plan, target amounts of 101,150 and 5,860 performance shares were granted to certain members of management in March and May of 2013, respectively; the averages of the high and low market prices on the grant dates, which approximates fair value, were $38.73 and $41.34 per share, respectively.

Also in March 2013, UIL Holdings granted a total of 2,033 shares of restricted stock to its President and Chief Executive Officer under the 2008 Stock Plan and in accordance with his employment agreement; the average of the high and low market price on the date of grant, which approximates fair value, was $38.73 per share. Such shares vest in equal annual installments over a five-year period. In May 2013, UIL Holdings granted a total of 2,177 shares of restricted stock to an executive under the Amended and Restated UIL Holdings 2008 Stock and Incentive Compensation Plan; the average of the high and low market price on the date of grant, which approximates fair value, was $41.34 per share. Such shares vest in May 2016.

Also in May 2013, UIL Holdings granted a total of 21,558 shares of restricted stock to non-employee directors under the 2008 Stock Plan; the average of the high and low market price on the date of grant, which approximates fair value, was $40.69 per share. Such shares vest in May 2014.

As of December 31, 2013, the total number of shares authorized for stock-based compensation plans was 4,150,000. Total stock-based compensation expense for the years ended December 31, 2013, 2012 and 2011 was $5.3 million, $4.9 million and $5.3 million, respectively.

Variable Interest Entities

UIL Holdings has identified GenConn as a variable interest entity (VIE), which is accounted for under the equity method. UIL Holdings is not the primary beneficiary of GenConn, as defined in ASC 810 “Consolidation,” because it shares control of all significant activities of GenConn with its joint venturer, NRG affiliates. As such, GenConn is not subject to consolidation. GenConn recovers its costs through CfDs, which are cost of service-based and have been approved by PURA. As a result, with the achievement of commercial operation by GenConn Devon and GenConn Middletown, UIL Holdings’ exposure to loss is primarily related to the potential for unrecovered GenConn operating or capital costs in a regulatory proceeding, the effect of which would be reflected in the carrying value of UIL Holdings’ 50% ownership position in GenConn and through “Income from Equity Investments” in UIL Holdings’ Consolidated Financial Statements. Such exposure to loss cannot be determined at this time. For further discussion of GenConn, see “–Equity Investments” as well as Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Equity Investment in Peaking Generation.”

UIL Holdings has identified the selected capacity resources with which UI has CfDs as VIEs and has concluded that UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these capacity resources. As such, UIL Holdings has not consolidated the selected capacity resources. UI’s maximum exposure to loss through these agreements is limited to the settlement amount under the CfDs as described in “–Derivatives – Contracts for Differences (CfDs)” above. UI has no requirement to absorb additional losses nor has UI provided any financial or other support during the periods presented that were not previously contractually required.

UIL Holdings has identified the entities for which UI is required to enter into long-term contracts to purchase Renewable Energy Credits (RECs) as VIEs. In assessing these contracts for VIE identification and reporting purposes, UIL Holdings has aggregated the contracts based on similar risk characteristics and significance to UI. UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these entities. UI’s exposure to loss is primarily related to the purchase and resale of the RECs, but, any losses incurred are recoverable through electric rates. For further discussion of RECs, see Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – New Renewable Source Generation.”

New Accounting Standards

In February 2013, the FASB issued updated guidance to ASC 220 “Comprehensive Income” which requires disclosure of amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present either on the face of the Consolidated Statements of Income or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required to be reclassified to net income in its entirety in the same reporting period. For amounts not reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide additional detail about those amounts. The guidance was effective prospectively for the first quarter of 2013. The adoption of this update did not have a material impact on UIL Holdings’ consolidated financial statements.

In July 2013, the FASB issued updated guidance to ASC 740 “Income Taxes” which prescribes the presentation of an unrecognized tax benefit when a net operating loss carry forward, a similar tax loss, or a tax credit carry forward exists. This guidance is effective during interim and annual periods beginning after December 15, 2013 and is to be applied on a prospective basis. The implementation of this guidance is not expected to have a material impact on UIL Holdings’ consolidated financial statements.

CAPITALIZATION

CAPITALIZATION	12 Months Ended
CAPITALIZATION	Dec. 31, 2013
CAPITALIZATION [Abstract]	'
CAPITALIZATION	'
	(B) CAPITALIZATION

	Common Stock

	UIL Holdings had 56,462,507 shares of its common stock, no par value, outstanding as of December 31, 2013 and 50,665,114 shares of its common stock, no par value, outstanding at December 31, 2012. Not included in such shares were 276,845 and 209,469 shares of restricted stock as of December 31, 2013 and 2012, respectively. These cumulative shares of restricted stock are, however, recognized as outstanding for purposes of calculating basic earnings per share because such shares represent the net of the amount of deferred vested restricted stock, less the amount of non-deferred unvested restricted stock.

	On October 2, 2013, UIL Holdings issued 5,750,000 shares of its common stock at $37.25 per share in an underwritten public offering. This issuance included 750,000 shares issued upon the exercise by the underwriters of their over-allotment option. Net proceeds of the offering, including the over-allotment option, were approximately $206.4 million, after expenses and underwriting discounts, and were accounted for as an addition to common stock on UIL Holdings’ Consolidated Balance Sheet. UIL Holdings used the net proceeds from this issuance to repay short-term debt, which was incurred primarily to fund its regulated subsidiaries in order to maintain their targeted capital structures, and for general corporate purposes. Repayment of short-term debt enhances the UIL Holdings’ available liquidity, which strengthens its ability to provide ongoing financial support to its regulated subsidiaries.

	Restricted stock activity for 2013 is as follows:

			Number				Weighted Average
			of Shares				Grant Date
							Fair Value
	Nonvested Balance – December 31, 2012			74,131			$	30.49
	Granted			25,768			$	40.59
	Forfeited			(1,672	)		$	29.91
	Vested			(67,307	)		$	30.5
	Nonvested Balance – December 31, 2013			30,920			$	38.9

	As of December 31, 2013, total unrecognized costs for non-vested restricted stock awards were $0.5 million. The weighted-average period over which the restricted stock costs will be recognized is 9 months.

	Performance share activity for 2013 is as follows:

			Number				Weighted Average
			of Performance				Grant Date
			Shares				Fair Value
	Nonvested Balance – December 31, 2012			325,888			$	31.39
	Granted			107,010			$	38.87
	Forfeited			(36,740	)			N/A
	Vested			(61,150	)		$	28.53
	Nonvested Balance – December 31, 2013			335,008			$	34.62

	As of December 31, 2013, total unrecognized costs for performance shares were $2.1 million. The weighted-average period over which the performance-share costs will be recognized is 11 months.

	The weighted average grant date fair value of all restricted stock and performance shares granted during the year was $39.21, $34.33, and $33.33 for the years ended December 31, 2013, 2012, and 2011 respectively.

	Stock option transactions for 2013, 2012 and 2011 are as follows:

			Number				Option Price			Average
			of Options				per Share			Exercise
										Price
	Balance – December 31, 2010			134,994				$21.68-$34.51			$31.70
	Granted			-				N/A			N/A
	Forfeited			(7,910	)			N/A			N/A
	Exercised			(28,864	)			$21.68-$31.25			N/A
	Balance – December 31, 2011			98,220				$21.68-$33.96			$33.39
	Granted			-				N/A			N/A
	Forfeited			(38,000	)			N/A			N/A
	Exercised			(56,887	)			$31.25-$33.96			N/A
	Balance – December 31, 2012			3,333				$21.68			$21.68
	Granted			-				N/A			N/A
	Forfeited			-				N/A			N/A
	Exercised			(3,333	)			21.68			N/A
	Balance – December 31, 2013			-				N/A			N/A

	Exercisable at December 31, 2011			98,220				$21.68-$33.96			$33.39
	Exercisable at December 31, 2012			3,333				$21.68			$21.68
	Exercisable at December 31, 2013			-				N/A			N/A


	There were no options outstanding as of December 31, 2013. As of December 31, 2012 and 2011, the weighted-average remaining contractual lives for those options outstanding were 0.3 years, and 0.5 years, respectively.

	Cash received from options exercised under all share-based payment arrangements for the years ended December 31, 2013, 2012 and 2011, was $0.1 million, $1.9 million, and $0.8 million, respectively. The actual tax benefit realized by UIL Holdings for the tax deductions from the exercises totaled $0.1 million for each of 2013, 2012 and 2011.

The shares issued to non-employee directors as well as employee performance shares and options are drawn from the 2008 Stock Plan.

Preferred Stock of Subsidiaries, Noncontrolling Interests

The preferred stock of subsidiaries are noncontrolling interests because they contain a feature that allows the holders to elect a majority of the subsidiary’s board of directors if preferred stock dividends are in default in an amount equivalent to four full quarterly dividends. Such a potential redemption-triggering event is not solely within the control of the subsidiary.

CNG has one 8.00% non-callable series of cumulative preferred stock authorized with a par value of $3.125 per share. As of December 31, 2013, there were 108,706 shares issued and outstanding with a value of approximately $0.3 million and 775,609 shares authorized but unissued.

On February 3, 2014, CNG announced an offer to purchase all of the issued and outstanding shares of CNG’s $3.125 Par Preferred Stock for a purchase price of $7.50 per share. The offer to purchase will expire on March 4, 2014.

Long-Term Debt
		December 31,
		2013				2012
		(In Thousands)
UIL Holdings
4.625% Unsecured Senior Notes, due 2020		$	450,000			$	450,000

UI
Pollution Control Revenue Bonds:

4.50% 2010 Series, due 2027			27,500				27,500
Auction Rate, 2003 Series, due 2033 (1)			64,460				64,460

Senior Unsecured Notes:

6.06% Senior Notes, Series A and B, due 2017			70,000				70,000
2.98% Senior Notes, Series A due 2019			31,000				31,000
3.61% Senior Notes, Series B and C and 6.26% Senior Notes, Series C and D, due 2022			162,500				162,500
6.51% Senior Notes, Series E and F due 2037			28,000				28,000
6.46% Senior Notes, Series A and 6.51%, Senior Notes, Series B, due 2018			100,000				100,000
6.61% Senior Notes, Series C, due 2020			50,000				50,000
5.61% Senior Notes, due 2025			50,000				50,000
6.09% Senior Notes, due 2040			100,000				100,000
4.89% Senior Notes, Series D and E, due 2042			87,000				87,000
3.95% Senior Notes, Series F, due 2023			75,000				-

Gas Companies
Senior Secured Notes:

3.88% - 7.50% Senior Secured Medium Term Note IV, due 2018 - 2041			100,000				100,000
5.77% - 6.38% Senior Secured Medium Term Notes III, due 2025 - 2037			85,000				85,000
6.88% - 7.95% Senior Secured Medium Term Notes I, due 2026 - 2028			29,000				29,000
10.06% First Mortgage Bond Series P, due 2019			10,000				10,000

Unsecured Notes:

4.76% - 9.60% Senior Unsecured Notes, due 2020 - 2021			19,635				21,090
6.85% - 9.10% Unsecured Medium Term Notes, Series A, due 2013 - 2017			30,000				50,000
6.50% Unsecured Medium Term Note, Series D, due 2013			-				20,000
8.12% - 8.49% Unsecured Medium Term Notes, Series B, due 2014 - 2024			10,000				10,000
5.63% - 6.66% Unsecured Medium Term Notes, Series C, due 2035 - 2037			65,000				65,000
4.30% - 5.23% Medium Term Note, Series D, due 2028 - 2043			45,000				-
5.33% Senior Notes, Series A, due 2043			15,000				-

Long-Term Debt			1,704,095				1,610,550
Less: Current portion of long-term debt (2)			11,834				48,296
Less: Unamortized discount			2,597				2,916
Plus: Unamortized premium			34,178				41,016
Net Long-Term Debt		$	1,723,842			$	1,600,354

(1) On December 31, 2013, the interest rate on the Bonds was 0.34%. The interest rate on these Bonds is reset through an auction held every 35 days.
(2) Includes the current portion of unamortized premium.

The amount of restricted net assets as of December 31, 2013 was approximately $557.2 million, of which approximately $118.2 million relates to UI’s equity investment in GenConn. Substantially all of the respective utility’s properties are pledged as collateral for the applicable Senior Secured Medium Term Notes and First Mortgage Bonds.

The weighted-average remaining fixed rate period of outstanding long-term debt obligations of UIL Holdings and its subsidiaries as of December 31, 2013 was 11.7 years, at an average interest rate of 5.44%.

The fair value of UIL Holdings’ long-term debt was $1.8 billion and $1.9 billion as of December 31, 2013 and 2012, respectively, which was estimated by UIL Holdings based on market conditions. The expenses to issue long‑term debt are deferred and amortized over the life of the respective debt issue or the fixed interest-rate period in the case of pollution control revenue bonds.

Information regarding maturities and mandatory redemptions/repayments are set forth below:

		2014				2015			2016			2017		2018 &
		2014				2015			2016			2017		thereafter
(In Thousands)
Maturities		$	6,455			$	1,455		$	11,455		$	91,455	$	1,593,275

On October 25, 2013, UI entered into a note purchase agreement with a group of institutional accredited investors providing for the sale to such investors on October 25, 2013 of senior unsecured 3.95% notes in the principal amount of $75 million, due on October 25, 2023. UI used the net proceeds from this long-term debt issuance to repay short-term debt and for general corporate purposes.

On October 25, 2013, CNG entered into a note purchase agreement with a group of qualified institutional buyers providing for the sale to such buyers on October 25, 2013 of senior unsecured 4.30% notes in the principal amount of $25 million, due on October 25, 2028 and 5.23% notes in the principal amount of $20 million, due on October 25, 2043. CNG used $20 million of the net proceeds of this long-term debt issuance to replenish cash that had been used to repay $20 million of debt that matured in September 2013 and used $20 million of the net proceeds to repay $20 million of 6.50% Medium Term Notes, Series D, due December 15, 2013. CNG expects to use the remainder of the net proceeds for capital expenditures and general corporate purposes.

On October 25, 2013, Berkshire entered into a note purchase agreement with a group of institutional accredited investors providing for the sale to such investors on December 10, 2013 of senior unsecured 5.33% notes in the principal amount of $15 million, due on December 10, 2043. Berkshire used the net proceeds of this long‑term debt issuance for the repayment of short-term debt and expects to use the remaining net proceeds for general working capital, environmental expenditures and capital expenditures.

Due to conditions in the municipal bond market, UIL Holdings determined it was economically favorable to refinance multiple series of pollution control revenue bonds in the aggregate principal amount outstanding of $103.5 million with notes issued in the private placement market. On January 30, 2012, UI entered into a Note Purchase Agreement with a group of institutional accredited investors to issue $203.5 million principal amount of senior unsecured notes. On January 30, 2012, $103.5 million of such notes were issued as follows: 3.61%, Series B, due January 31, 2022, in the principal amount of $51.5 million and 4.89%, Series D, due January 30, 2042, in the principal amount of $52 million. On April 2, 2012, the remaining $100 million of such notes were issued as follows: 2.98%, Series A, due January 31, 2019, in the principal amount of $31 million, 3.61%, Series C, due January 31, 2022 in the principal amount of $34 million and 4.89%, Series E, due January 30, 2042, in the principal amount of $35 million.

REGULATORY_PROCEEDINGS

REGULATORY PROCEEDINGS	12 Months Ended
	Dec. 31, 2013
REGULATORY PROCEEDINGS [Abstract]	'
REGULATORY PROCEEDINGS	'
	(C) REGULATORY PROCEEDINGS

	In November 2012, pursuant to PA 12-148, PURA opened a docket to investigate UI’s and the Gas Companies’ performance in restoring service following Superstorm Sandy, which passed through Connecticut in October 2012. A final decision was issued on August 21, 2013, in which PURA found that the electric distribution companies and the gas local distribution companies performed their storm-related activities in a timely and effective manner and made recommendations for certain improvements.

	Electric Distribution and Transmission

	ISO-NE, an independent, not-for-profit corporation, is the Regional Transmission Organization (RTO) for New England. ISO-NE is responsible for the reliable operation of the region’s bulk electric power system, which includes UI’s electric system, and administration of the region’s wholesale electricity marketplace. ISO-NE also is responsible for the management of the comprehensive bulk electric power system and wholesale markets’ planning processes that address the region's electricity needs.

	Superstorm Sandy caused extensive damage to the electric system in UI's service territory and resulted in approximately 284,000 customer outages. In accordance with PURA regulatory decisions and past storm cost guidance, UI has established a regulatory asset for its storm-related expense. UI’s cost of repairing the damage resulting from the storm and restoring service to customers was approximately $35.8 million, of which approximately $13.9 million was capitalized as property plant and equipment and the remainder as a regulatory asset. As a result of PURA’s final decision in UI’s 2013 distribution rate case, a portion of this regulatory asset was disallowed. See “‑Rates” below for additional information regarding the recovery and disallowance of storm costs, including costs of Superstorm Sandy.

	Rates

	On February 15, 2013, UI filed an application to amend its existing distribution rate schedules for two rate years. On August 14, 2013, PURA issued a decision (the August Decision) which became effective on that date and which, among other things, increased the UI distribution and CTA allowed return on equity (ROE) from 8.75% to 9.15%, continued UI’s existing earnings sharing mechanism by which UI and customers share on a 50/50 basis all distribution earnings above the allowed ROE in a calendar year, continued the existing decoupling mechanism, and approved the establishment of the requested storm reserve. Additionally, the August decision disallowed approximately $22 million related to deferred storm costs and capital costs related to UI’s recently constructed administrative and operations buildings. As a result of these disallowances and other adjustments related to the rate proceeding, UIL Holdings recorded a one-time pre-tax write off of $17.5 million related to UI in the third quarter of 2013.

	On December 16, 2013, PURA issued a final decision on UI’s Petition for Reconsideration of PURA’s August Decision in UI’s distribution rate case. The final decision on the reconsideration restored approximately $6.8 million of deferred storm costs and approximately $2.7 million of capital costs related to UI’s recently constructed administrative and operations buildings which had been disallowed in the August Decision. As a result, UIL Holdings recorded a one-time pre-tax adjustment of approximately $9.2 million in the fourth quarter of 2013 to reverse such amounts written off in the third quarter of 2013 as a result of the August Decision. The resulting storm regulatory asset allowed for recovery totaled approximately $45 million. PURA’s final determination on the timing of recovery of the remaining storm regulatory asset, if any, after applying the revenue from the 2010 and 2012 earnings sharing along with the excess CTA revenue collections is expected in the second half of 2014. As of December 31, 2013, UI’s storm regulatory asset totaled approximately $14.8 million.

	On September 30, 2013, PURA approved UI’s revised distribution decoupling filings for the 2011 and 2012 rate years which included decoupling adjustments of $4.0 million and $6.4 million, respectively. UI began recovering these amounts from customers on October 1, 2013. The recovery period for the decoupling adjustments will run through September 30, 2014. On October 11, 2013, UI filed its distribution decoupling filing for the 2013 rate year under its previous rate case that ended on August 13, 2013 which included a decoupling adjustment of $0.9 million. On January 29, 2014, PURA approved UI’s decoupling filing for the 2013 rate year under its previous rate decision. The recovery period for the decoupling adjustment is from February 1, 2014 to September 30, 2014.

	Power Supply Arrangements

	UI’s retail electricity customers are able to choose their electricity supplier. Since January 1, 2007, UI has been required to offer standard service to those of its customers who do not choose a retail electric supplier and have a maximum demand of less than 500 kilowatts. In addition, UI is required to offer supplier of last resort service to customers who are not eligible for standard service and who do not choose to purchase electric generation service from a retail electric supplier licensed in Connecticut.

	UI must procure the power to serve its standard service load pursuant to a procurement plan approved by PURA. The procurement plan must provide for a portfolio of service agreements procured in a manner that maintains standard service cost volatility within reasonable levels. On October 10, 2012, PURA approved the Standard Service Procurement Plan (the Procurement Plan) submitted by DEEP’s procurement manager to PURA for approval as required by Connecticut law. The Procurement Plan, which was developed by the procurement manager, in consultation with UI, CL&P and the Connecticut Office of Consumer Counsel, provides for UI to continue to procure wholesale power for its standard service customers on a full requirements basis pursuant to contracts with a maximum duration of 12 months, with the delivery of such wholesale power to commence no later than six months from the applicable bid day. The length of term and tranche sizes may be modified by the mutual agreement of UI and the procurement manager.

	UI has wholesale power supply agreements in place for its entire standard service load for the first half of 2014 and for 80% of its standard service load for the second half of 2014. UI determined that its contracts for standard service and supplier of last resort service are derivatives under ASC 815 “Derivatives and Hedging” and elected the “normal purchase, normal sale” exception under ASC 815 “Derivatives and Hedging.” UI regularly assesses the accounting treatment for its power supply contracts. These wholesale power supply agreements contain default provisions that include required performance assurance, including certain collateral obligations, in the event that UI’s credit rating on senior debt were to fall below investment grade. If UI’s credit rating were to decline one rating at Standard & Poor’s or two ratings at Moody’s and UI were to be placed on negative credit watch, monthly amounts due and payable to the power suppliers would be accelerated to semi-monthly payments. UI’s credit rating would have to decline two ratings at Standard & Poor’s and three ratings at Moody’s to fall below investment grade. If this were to occur, UI would have to deliver collateral security in an amount equal to the receivables due to the sellers for the thirty-day period immediately preceding the default notice. If such an event had occurred as of December 31, 2013, UI would have had to post an aggregate of approximately $10.6 million in collateral.

	In addition, UI is permitted to seek long-term contracts for up to 20% of its standard service requirements and Connecticut Class I Renewable Energy Certificates for UI’s standard service customers that will result in an economic benefit to ratepayers, both in terms of risk and cost mitigation. UI continues to keep apprised of possible long-term contracts that could benefit customers, but has not executed any long-term contracts.

	New Renewable Source Generation

	Under Connecticut Public Act No. 11-80, An Act Concerning the Establishment of the Department of Energy and Environmental Protection and Planning for Connecticut's Energy Future (PA 11-80), Connecticut electric utilities are required to enter into long-term contracts to purchase RECs from small renewable generators located on customer premises. Under this program, UI is required to enter into contracts totaling approximately $200 million in commitments over an approximate 21-year period. The obligations will phase in over a six-year solicitation period, and are expected to peak at an annual commitment level of about $13.6 million per year after all selected projects are online. Upon purchase, UI accounts for the RECs as inventory. UI expects to partially mitigate the cost of these contracts through the resale of the RECs. PA 11-80 provides that the remaining costs of these contracts, including any gain or loss resulting from the resale of the RECs, are fully recoverable through electric rates. As of December 31, 2013, UI had entered into contracts totaling up to $2.9 million annually in payments for 15-year delivery terms commencing in 2013 and 2014.

	Section 127 of PA 11-80 provided for the development of up to 30 MW of small Class I renewable generation projects in Connecticut. Specifically the statute authorized DEEP to procure up to 10 MW of renewable generation from the market and allows each of UI and CL&P to build, own or operate facilities totaling up to 10 MW each.

	In December 2011, DEEP announced that in accordance with the authorization for it to procure up to 10 MW of Class I renewables, it had selected two 5 MW solar projects in CL&P service territory and CL&P executed contracts with the developers to purchase energy and associated products from both projects. These contracts and the associated cost recovery have been approved by DEEP and PURA, respectively. UI and CL&P executed a sharing arrangement, pursuant to which UI will pay 20% of the costs, and receive 20% of the benefits, associated with the projects. Pursuant to PURA’s approval of the cost recovery, the payments made to projects are fully recoverable through electric rates.

	Additionally, in January 2012, UI filed its proposal with PURA outlining UI’s renewable connections program under PA 11-80 through which UI would develop up to 10 MW of renewable generation for recovery on a cost of service basis. PURA issued a final decision in July 2012 approving the construction of one solar facility and two fuel cell facilities. The decision approved an ROE equal to UI’s then currently allowed distribution ROE, which was 8.75%, over the life of the facility. UI had requested an ROE of 9.5%. In September 2012, PURA reopened the proceeding on its own motion. On August 28, 2013, UI and the Prosecutorial Division of PURA entered into a settlement agreement addressing the issues of disagreement, including balancing the risks of the projects with the ROE. On October 23, 2013, PURA approved the settlement. The settlement establishes a base ROE to be calculated as the greater of: (A) the current UI authorized distribution ROE plus 25 basis points and (B) current authorized distribution ROE for CL&P, less target equivalent market revenues (reflected as 25 basis points). In addition, UI will retain a percentage of the market revenues from the project, which percentage is expected to equate to approximately 25 basis points on a levelized basis over the life of the project. Under the settlement, UI agreed to submit to PURA the budget for the approximately 7.8 MW in projects identified in its January 2012 filing within three months of the PURA approval, which period was extended to February 21, 2014, and to submit project details and budgets for the remaining 2.2 MW within twelve months. If PURA fails to approve, or rejects or modifies the budget in any way, UI has the right to cancel the development of such project with no further liability. The Settlement also provides that construction of any of these projects will be subject to the receipt of all required permits and approvals acceptable in form and substance to UI.

	Under Section 6 of Connecticut Public Act 13-303 (PA 13-303), DEEP was authorized to direct Connecticut’s electric distribution companies, including UI, to enter into contracts for energy and/or RECs from Class I renewable resources in a quantity of up to 4% of the electric distribution companies’ distribution load. On July 8, 2013, DEEP issued a request for proposals (RFP), and directed UI and CL&P to enter into power purchase agreements with the winning bidders. On September 19, 2013, UI entered into contracts with two of the winning bidders which were subsequently approved by PURA. One contract is for 48.1 MW produced by a 250 MW wind farm to be built in Maine, and the second is for 3.8 MW produced by a 20 MW solar project to be built in Connecticut. The quantity of energy and RECs to be purchased under these contracts total approximately 3.5% of UI’s distribution load. PA 13-303 provides that costs of any such agreement will be fully recoverable through electric rates. On December 18, 2013, Allco Finance Limited, an unsuccessful bidder in the RFP, filed a complaint against DEEP in the United States District Court in Connecticut alleging that DEEP’s direction to UI and CL&P to enter into the contracts violated the Supremacy Clause of the U.S. Constitution and the Federal Power Act by setting wholesale electricity rates. UI is not a party to the complaint.

	Also under Section 8 of PA 13-303, DEEP is authorized to direct Connecticut’s electric distribution companies, including UI, to enter into contracts for energy and/or RECs from biomass, landfill gas and small hydro projects that qualify as Connecticut Class I renewable resources in a quantity up to 4% of the electric distribution companies’ distribution load. On December 26, 2013, DEEP directed UI to enter into three long-term contracts to purchase RECs from existing biomass facilities in New England. In January 2014, UI entered into three contracts for the purchase of RECs associated with an aggregate of 5.7 MW of energy production from biomass plants in New England. The contracts are currently pending PURA approval. PA 13-303 provides that costs of any such agreements will be fully recoverable through electric rates.

	Transitional Standard Offer Incentive (TSO)

	State legislation significantly restructured the electric utility industry in Connecticut in 1998 and 2003. The primary restructuring legislation includes Public Act 98-28 (the 1998 Restructuring Legislation) and Public Act 03-135, as amended in part by Public Act 03-221 (the 2003 Restructuring Legislation). The 2003 Restructuring Legislation provided for PURA to establish an incentive plan for the procurement of long-term contracts for transitional standard offer service that compares UI’s actual average contract price to a regional average price for electricity, making adjustments as deemed appropriate by PURA. For each of 2004, 2005 and 2006, if UI’s price was lower than the average, the legislation provided for the plan to allocate $0.00025/kilowatt-hour of transitional standard offer service to the distribution company. PURA issued a final decision in January 2009 that found UI was not eligible for a procurement incentive for 2004. UI appealed PURA’s final decision to the state superior court. By decision filed February 5, 2010, the superior court determined that PURA did not apply the proper standard in determining whether UI qualified for the incentive and that PURA made other errors, and remanded the case to PURA for further proceeding in accordance with the court's decision. PURA appealed the superior court’s decision to the state appellate court. On October 2, 2012, UI, CL&P and the Connecticut Office of Consumer Counsel (OCC) filed with PURA a joint motion for approval of a settlement agreement by and among UI, CL&P, and the OCC. On October 31, 2012, PURA issued a final decision approving the settlement agreement which resolves all of the issues relating to the incentive for the procurement of power for 2004 through 2006. The settlement agreement provides that UI has met the statutory standard for receiving 2005 and 2006 TSO incentives previously collected of approximately $2.7 million, which were recorded in the third quarter of 2012 and are included in “Other Income and (Deductions)” in UIL Holdings’ Consolidated Statement of Income. The settlement agreement also provides that no further amounts are due from UI to customers relating to the 2004 incentive in light of amounts refunded to customers in 2009.

	Transmission

	PURA decisions do not affect the revenue requirements determination for transmission, including the applicable return on equity (ROE), which are within the jurisdiction of the FERC. The FERC has issued orders establishing allowable ROEs for transmission projects of transmission owners in New England, including UI. The FERC established a base-level ROE of 11.14%, as well as a 50 basis point ROE adder on Pool Transmission Facilities (PTF) for participation in the RTO for New England and a 100 basis point ROE incentive for projects included in the ISO-NE Regional System Plan that were completed and on line as of December 31, 2008.

	UI’s overall transmission ROE is determined by the mix of UI’s transmission rate base between new and existing transmission assets, and whether such assets are PTF or non-PTF. UI’s transmission assets are primarily PTF. For 2013, UI’s overall allowed weighted-average ROE for its transmission business was 12.2%, excluding the impact of the reserve related to the September 2011complaint discussed below. UI recovers its transmission revenue requirements on a prospective basis, subject to reconciliation with actual revenue requirements. UI is required to file information regarding its approved formula rates on an annual basis with the FERC.

	In September 2011, several New England governmental entities, including PURA, the Connecticut Attorney General and the Connecticut Office of Consumer Counsel, filed a joint complaint with the FERC against ISO-NE and several New England transmission owners, including UI, claiming that the current approved base ROE used in calculating formula rates for transmission service under the ISO-NE Open Access Transmission Tariff by the New England transmission owners of 11.14% is not just and reasonable and seeking a proposed reduction of the base ROE to 9.20% to be effective for the period of October 1, 2011 through December 31, 2012. A 25 basis point change in the weighted-average ROE for UI’s transmission business would change net income by approximately $0.6 million annually, for example.

	On August 6, 2013, the presiding Administrative Law Judge issued an initial decision finding that the existing base ROE was unjust and unreasonable, and that the just and reasonable base ROE is 10.6% for the refund period of October 1, 2011 through December 31, 2012 and, for the period after a final opinion is issued by the FERC, 9.7%, prior to any adjustments that may be applied by the FERC in a final order based on the change in 10-year U.S. Treasury Bond rates from the date hearings closed to the date of the FERC’s order. We expect the FERC to issue its final opinion in 2014. UI recorded a reserve for the refund period of $2.6 million during the third quarter based upon its assessment of the ultimate outcome of the proceeding.

	In December 2012, various additional parties filed a complaint with the FERC against several New England transmission owners, including UI, seeking a proposed reduction of the base ROE to 8.70%, effective January 1, 2013. The transmission owners filed an answer and request for dismissal in January 2013, including opposition to the establishment of a second 15 month refund period because the complaint seeks substantially the same relief against the same respondents but for a different 15 month period as the pending complaint of governmental entities. The complainants filed their answer to the transmission owners’ answer in February 2013. UI is unable to predict the outcome of this proceeding at this time.

	New England East-West Solution

	Pursuant to an agreement with CL&P (the Agreement), UI has the right to invest in, and own transmission assets associated with, the Connecticut portion of CL&P’s New England East West Solution (NEEWS) projects to improve regional energy reliability. NEEWS consists of four inter-related transmission projects being developed by subsidiaries of Northeast Utilities (NU), the parent company of CL&P, in collaboration with National Grid USA. Three of the projects have portions located in Connecticut: (1) the Greater Springfield Reliability Project, which is substantially complete, (2) the Interstate Reliability Project, which has Connecticut Siting Council approval and (3) the Central Connecticut Reliability Project being studied now as part of the "Greater Hartford Central Connecticut Study" (GHCC) due to the expanded scope of ISO-NE’s reassessment. GHCC transmission solutions are being considered and a set of preferred solutions are expected to be identified by ISO-NE in 2014.

	Under the terms of the Agreement, UI has the option to make quarterly deposits to CL&P in exchange for ownership of specific NEEWS transmission assets as they are placed in service. UI has the right to invest up to the greater of $60 million or an amount equal to 8.4% of CL&P’s costs for the Connecticut portions of the NEEWS projects. Based upon the current projected costs, this amount is approximately $60 million. As CL&P places assets in service, it will transfer title to certain NEEWS transmission assets to UI in proportion to UI’s investments, but CL&P will continue to maintain these portions of the transmission system pursuant to an operating and maintenance agreement (O&M Agreement) with UI. Any termination of the Agreement pursuant to its terms would have no effect on the assets previously transferred to UI.

Deposits associated with NEEWS are recorded as assets at the time the deposit is made and they are reported in the ‘Other’ line item within the Deferred Charges and Other Assets section of the consolidated balance sheet. When title to the assets is transferred to UI, the amount of the corresponding deposit is reclassified from other assets to plant-in-service on the balance sheet and shown as a non-cash investing activity in the consolidated statement of cash flows.

As of December 31, 2013, UI had made aggregate deposits of $35.1 million under the Agreement since its inception, with assets valued at approximately $24.6 million having been transferred to UI, as follows: In September 2012, CL&P transferred approximately $6.2 million of transmission assets associated with the Greater Springfield Reliability Project, and in February 2013, CL&P transferred approximately $18.4 million of transmission assets, representing the remaining portion of the Greater Springfield Reliability Project. UI earned pre-tax income on deposits, net of transferred assets, of approximately $1.5 million, $1.6 million and $1.0 million in the years ended December 31, 2013, 2012 and 2011, respectively. On February 7, 2014, UI made an additional deposit in NEEWS of approximately $1 million.

Other Proceedings

UI generally has several regulatory proceedings open and pending at PURA at any given time. Examples of such proceedings include an annual PURA review and reconciliation of Systems Benefits Charges (SBC) revenues and expenses, dockets to consider specific restructuring or electricity market issues, consideration of specific rate or customer issues, and review of conservation programs.

UI files semi-annual true-ups with PURA regarding Bypassable Federally Mandated Congestion Charges and Non-Bypassable Federally Mandated Congestion Charges. These customer charges relate to “congestion costs” associated with not having adequate transmission infrastructure to move energy from the generating sources to the consumer and costs associated with ensuring adequate capacity on the electric system, such as peaking generation and capacity CfDs with generators. These costs change from time to time and the semi-annual true-ups provide a mechanism for the electric distribution companies to adjust the charges to customers that allow the companies to recover the Federally Mandated Congestion Charges.

UI makes a semi-annual transmission adjustment clause (TAC) filing with PURA setting forth its actual transmission revenues, projected transmission revenue requirement, and the required TAC charge or credit so that any under- or over-collections of transmission revenues from prior periods are reconciled along with the expected revenue requirements for the next six months from filing. PURA holds an administrative proceeding to approve the TAC charge or credit and holds a hearing to determine the accuracy of customer billings under the TAC. The TAC tariff and this semi-annual change of the TAC charge or credit facilitates the timely matching of transmission revenues and transmission revenue requirements.

Equity Investment in Peaking Generation

UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut. The two peaking generation plants, GenConn Devon and GenConn Middletown, are both participating in the ISO-New England markets. PURA has approved revenue requirements for the period from January 1, 2014 through December 31, 2014 of $30.8 million and $37.5 million for GenConn Devon and GenConn Middletown, respectively. In addition, PURA has ruled that GenConn project costs incurred that were in excess of the proposed costs originally submitted in 2008 were prudently incurred and are recoverable. Such costs are included in the determination of the 2014 approved revenue requirements.

Gas Distribution

Rates

Utilities are entitled by Connecticut and Massachusetts statute to charge rates that are sufficient to allow them an opportunity to cover their reasonable operating and capital costs, to attract needed capital and to maintain their financial integrity, while also protecting relevant public interests.

The allowed returns on equity established by PURA are 9.18% and 9.36% for CNG and SCG, respectively. Berkshire’s rates are established by the DPU. Berkshire’s 10-year rate plan, which was approved by the DPU and included an approved ROE of 10.5%, expired on January 31, 2012. Berkshire continues to charge the rates that were in effect at the end of the rate plan.

SCG and CNG each have purchased gas adjustment clauses and Berkshire has a cost of gas adjustment clause, approved by PURA and DPU, respectively, which enable them to pass their reasonably incurred cost of gas purchases through to customers. These clauses allow utilities to recover costs associated with changes in the market price of purchased natural gas, substantially eliminating exposure to natural gas price risk. Additionally, Berkshire’s mechanism allows for the recovery of the gas-cost portion of bad debt.

On July 8, 2013, CNG filed an application to amend its existing base delivery rate. On January 22, 2014, PURA issued a final decision, with an effective date of January 10, 2014, which, among other things, approved an allowed ROE of 9.18%, a decoupling mechanism, and two separate ratemaking mechanisms that reconcile actual revenue requirements related to CNG’s cast iron and bare steel replacement program and a system expansion mechanism. Additionally, the final decision requires the establishment of an earnings sharing mechanism by which CNG and customers share on a 50/50 basis all earnings above the allowed ROE in a calendar year. The decision also allows CNG, on a provisional basis, to reflect the increased rate base resulting from the accumulated deferred income tax (ADIT) impacts of the election of Section 338(h)(10) of the Internal Revenue Code upon acquisition by UIL Holdings. The decision requires CNG to seek a private letter ruling from the Internal Revenue Service with regards to the specific question of whether or not, after extinguishment of an ADIT balance, a directive by a public utility commission to institute a ratemaking mechanism to reflect a credit to ratepayers of ADIT benefits lost through a Section 338(h)(10) election would result in a normalization violation. CNG had submitted expert testimony to PURA that such a ratemaking mechanism in these circumstances would result in a normalization violation. The decision states that in the event of a ruling from the Internal Revenue Service stating that imposing such a ratemaking mechanism would not create a normalization violation, PURA will adjust rates to offset the ratemaking impacts of the 338(h)(I0) election on rate base.

On June 14, 2013, CNG, SCG and Yankee Gas Services Company, an unrelated regulated gas distribution company, filed a comprehensive joint 10 year natural gas expansion plan (“Expansion Plan”) with PURA and DEEP. The plan was in response to the gas expansion goals proposed in the Connecticut Governor’s Comprehensive Energy Strategy and Public Act 13-298. The Expansion Plan included a set of recommendations designed to help meet the statewide goal of adding approximately 280,000 new customers, including providing more flexibility to minimize a new customer’s contribution to the cost to serve them, providing tools to help fund natural gas conversion costs, establishing a process to extend natural gas service for interested customers who are further away from the main gas line, and allowing utilities to secure additional pipeline capacity coming into Connecticut. PURA issued its final Decision on November 22, 2013. In this decision PURA approved new System Expansion (SE) rates exclusively for new on and off-main customers commencing service on or after January 1, 2014. These rates include a 10% premium distribution component for on-main customers and a 30% premium for off-main customers. The SE rates are complemented by new business rules that extend the Companies’ financial hurdle rate model from a 20-year to a 25-year time horizon, which will reduce the customer’s contributions to any construction costs, and allow the grouping of customers to help reduce or eliminate new customer contributions to system expansion. A separate new business reconciliation mechanism is also approved that reconciles the actual new business revenue requirements each year with the revenues received from the new business customers. As a result of the reconciliation, any shortfall or surplus in revenues will be charged or credited to existing firm customers. This ensures the timely recovery of new business capital investments and any associated expenses.

Approval for the Issuance of Debt

Long-term debt issuances require regulatory authorization which is typically obtained for a specified amount of debt to be issued during a specified period of time.

Berkshire has DPU approval to issue, from time to time, long-term debt in an aggregate principal amount not to exceed $20 million through December 14, 2014. Berkshire is authorized to use the proceeds from any such debt issuances for the following purposes: (1) to finance capital expenditures; (2) to refinance short-term debt; (3) to pay anticipated environmental expenditures; (4) to provide general working capital; and (5) any other purposes as the DPU may authorize. On December 10, 2013, Berkshire issued $15 million of senior unsecured notes pursuant to such DPU approval.

Gas Supply Arrangements

The Gas Companies satisfy their natural gas supply requirements through purchases from various producer/suppliers, withdrawals from natural gas storage capacity contracts and winter peaking supplies and resources. The Gas Companies operate diverse portfolios of gas supply, firm transportation capacity, gas storage and peaking resources. Actual reasonable gas costs incurred by each of the Gas Companies are passed through to customers through state regulated purchased gas adjustment mechanisms, subject to regulatory review.

The Gas Companies purchase the majority of their natural gas supply at market prices under seasonal, monthly or mid-term supply contracts and the remainder is acquired on the spot market. The Gas Companies diversify their sources of supply by amount purchased and location. The Gas Companies primarily acquire gas at various locations in the US Gulf of Mexico region, in the Appalachia region and in Canada.

The Gas Companies acquire firm transportation capacity on interstate pipelines under long-term contracts and utilize that capacity to transport both natural gas supply purchased and natural gas withdrawn from storage to the local distribution system. Collectively, the Gas Companies hold approximately 100 firm transportation contracts on 12 different pipelines. Three of those pipelines, Tennessee Gas Pipeline, Algonquin Gas Transmission and Iroquois Gas Transmission, interconnect with one or more of the Gas Companies’ distribution system and the other pipelines provide indirect services upstream of the city gates. The prices and terms and conditions of the long-term contracts for firm transportation capacity are regulated by the FERC. The actual reasonable costs of such contracts are passed through to customers through state regulated purchased gas adjustment mechanisms. The future obligations under these contracts as of December 31, 2013 are as follows:

		(In Thousands)
2014			126,485
2015			112,665
2016			99,467
2017			72,369
2018			42,609
2019-after			72,979
		$	526,574

The Gas Companies acquire firm underground natural gas storage capacity using long-term contracts and fill the storage facilities with gas in the summer months for subsequent withdrawal in the winter months. Collectively, the Gas Companies hold 24 gas storage contracts with seven different storage contractors. The storage facilities are located in Pennsylvania, New York, West Virginia and Michigan.

Winter peaking resources are primarily attached to the local distribution systems and are either owned or are contracted for by the Gas Companies, each of which is a Local Distribution Company. Each LDC owns or has rights to the natural gas stored in a Liquefied Natural Gas facility directly attached to its distribution system.

SHORTTERM_CREDIT_ARRANGEMENTS

SHORT-TERM CREDIT ARRANGEMENTS	12 Months Ended
SHORT-TERM CREDIT ARRANGEMENTS	Dec. 31, 2013
SHORT TERM CREDIT ARRANGEMENTS [Abstract]	'
SHORT-TERM CREDIT ARRANGEMENTS	'
	(D) SHORT‑TERM CREDIT ARRANGEMENTS

	UIL Holdings, UI, CNG, SCG, and Berkshire are parties to a revolving credit agreement with a group of banks that will expire on November 30, 2016 (the UIL Holdings Credit Facility). The borrowing limit under the UIL Holdings Credit Facility is $400 million, all of which is available to UIL Holdings, $250 million of which is available to UI, $150 million of which is available to each of CNG and SCG, and $25 million of which is available to Berkshire. The UIL Holdings Credit Facility permits borrowings at fluctuating interest rates and also permits borrowings for fixed periods of time specified by each Borrower at fixed interest rates determined by the Eurodollar interbank market in London (LIBOR). The UIL Holdings Credit Facility also permits the issuance of letters of credit of up to $50 million.

	As of December 31, 2013, there were no borrowings outstanding under the UIL Holdings Credit Facility. UIL Holdings has outstanding standby letters of credit in the aggregate amount of $4.4 million, which expire on June 16, 2015 January 31, 2015. Available credit under the UIL Holdings Credit Facility at December 31, 2013 totaled $395.6 million for UIL Holdings and its subsidiaries in the aggregate. UIL Holdings records borrowings under the UIL Holdings Credit Facility as short‑term debt, but the UIL Holdings Credit Facility provides for longer term commitments from banks allowing UIL Holdings to borrow and reborrow funds, at its option, until the facility’s expiration, thus affording UIL Holdings flexibility in managing its working capital requirements.

	As of December 31, 2013, UIL Holdings had no short-term borrowings outstanding under its money market loan arrangement with JPMorgan Chase Bank.

	In October 2012, UIL Holdings entered into a credit agreement with a borrowing limit of $100 million that expired on October 31, 2013 (the Credit Agreement). The outstanding balance was repaid upon expiration.

	Information with respect to short-term borrowings is set forth below:

		2013			2012
		($ In Thousands)
	UIL Holdings

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	202,000		$	168,000
	Average aggregate short-term borrowings outstanding during the year*	$	152,455		$	109,268
	Weighted average interest rate*		1.43	%		1.61	%
	Principal amounts outstanding at year-end	$	-		$	157,000

	UI

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	60,000		$	243,000
	Average aggregate short-term borrowings outstanding during the year*	$	13,510		$	78,533
	Weighted average interest rate*		1.4	%		1.58	%
	Principal amounts outstanding at year-end	$	-		$	30,000

	Gas Companies

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	-		$	6,000
	Average aggregate short-term borrowings outstanding during the year*	$	-		$	128
	Weighted average interest rate*		0	%		1.59	%
	Principal amounts outstanding at year-end	$	-		$	-

	* Average short‑term borrowings represent the sum of daily borrowings outstanding, weighted for the number of days outstanding and divided by the number of days in the period. The weighted average interest rate is determined by dividing interest expense by the amount of average borrowings.

INCOME_TAXES

INCOME TAXES	12 Months Ended
INCOME TAXES	Dec. 31, 2013
INCOME TAXES [Abstract]	'
INCOME TAXES	'
	(E) INCOME TAXES

			2013				2012				2011
			(In Thousands)
	Income tax expense consists of:
	Income tax provisions:
	Current
	Federal		$	(443	)		$	5,830			$	(16,626	)
	State			(1,149	)			1,110				(3,951	)
	Total current			(1,592	)			6,940				(20,577	)
	Deferred
	Federal			64,931				61,510				72,840
	State			6,164				6,611				10,433
	Total deferred			71,095				68,121				83,273

	Investment tax credits			(195	)			(195	)			(195	)

	Total income tax expense		$	69,308			$	74,866			$	62,501

	Total income taxes differ from the amounts computed by applying the federal statutory tax rate to income before taxes. The reasons for the differences are as follows:

			2013				2012				2011
			(In Thousands)

	Book income before income taxes		$	184,625			$	178,567			$	162,211

	Computed tax at federal statutory rate		$	64,619			$	62,499			$	56,774
	Increases (reductions) resulting from:
	Investment tax credits			(195	)			(195	)			(195	)
	Allowance for equity funds used during construction			(3,784	)			(2,749	)			(3,689	)
	Amortization of nuclear plant regulatory assets			6,867				9,334				8,885
	State income taxes, net of federal income tax benefits			3,259				5,018				4,214
	Other items, net			(1,458	)			959				(3,488	)

	Total income tax expense		$	69,308			$	74,866			$	62,501

	Effective income tax rates			37.5	%			41.9	%			38.5	%

	For 2013 and 2012, the combined statutory federal and state income tax rate was 40.9%. In 2011, the combined statutory federal and state income tax rate for UIL Holdings was 40.4%. Legislation enacted in Connecticut in 2011 increased the surcharge on the corporation business tax for the years 2012 and 2013. This additional surcharge increased the statutory rate of the Connecticut corporation business tax from 8.25% to 9% and increased the combined statutory federal and state income tax rate for UIL Holdings for 2012 and 2013 to 40.9%.

	Differences in the treatment of certain transactions for book and tax purposes occur which cause the rate of UIL Holdings’ reported income tax expense to differ from the statutory tax rate described above. The effective income tax rate for the year ended December 31, 2013 was 37.5%, as compared to 41.9% for the year ended December 31, 2012. The decrease in the 2013 effective income tax rate was primarily due to lower non-normalized nuclear stranded cost amortization due to the CTA being fully amortized in the third quarter of 2013, lower state income tax expense and higher equity allowance for funds used during construction.

	Federal income tax legislation has provided for accelerated capital recovery for federal income tax purposes for certain capital additions placed in service during 2011, 2012 and 2013. As a result, during these periods, UIL Holdings recognized accelerated tax deductions for capital recovery that resulted in cash benefits that were realized through lower cash requirements for federal income tax deposits.

	As of December 31, 2011, UIL had gross unrecognized tax benefits of approximately $13.7 million and $0.5 million of interest related to repair and maintenance costs it had previously capitalized for tax purposes. None of these uncertainties would impact the effective tax rate if recognized. Effective 2012, UIL Holdings changed its cumulative treatment for these costs to comply with a recently revised IRS regulation enabling UIL Holdings to fully reverse its uncertain tax position and associated interest. In September 2013, the U.S. Treasury issued final regulations that provide revised rules for the tax treatment of tangible property costs, including the treatment of repair and maintenance costs. These regulations are not expected to have a material impact on its consolidated financial statements.

	The following table sets forth a reconciliation of the changes in the gross income tax reserves for the years ended December 31, 2013 and 2012:

			2013				2012
			(In Thousands)
	Balance as of December 31		$	-			$	13,676
	Increases for tax positions related to current year			-				-
	Reductions for tax positions of prior years			-				(13,676	)
	Balance as of December 31		$	-			$	-

	UIL Holdings and its subsidiaries are subject to the United States federal income tax statutes administered by the Internal Revenue Service (IRS). UIL Holdings and its subsidiaries are also subject to the income tax statutes of the State of Connecticut and the Commonwealth of Massachusetts. As of December 31, 2013, the tax years 2010, 2011, 2012 and 2013 are open and subject to audit for federal, Connecticut, and Massachusetts income tax purposes.

	The Company files a consolidated federal income tax return with its subsidiaries, all of which have joint and several liability for any potential assessments against the consolidated group.

	ASC 740 requires that all current deferred tax assets and liabilities within each particular tax jurisdiction be offset and presented as a single amount in the Consolidated Balance Sheet. A similar procedure is followed for all non-current deferred tax assets and liabilities. Amounts in different tax jurisdictions cannot be offset against each other. The amount of deferred income taxes as of December 31, 2013 and 2012 included on the following lines of the Consolidated Balance Sheet is as follows:

			2013				2012
			(In Thousands)
Assets:
Deferred income taxes		$	21,742			$	41,605
Liabilities:
Deferred income taxes			540,542				462,940
Deferred income taxes – net		$	518,800			$	421,335

The following table summarizes UIL Holdings’ deferred income tax assets and liabilities as of December 31, 2013 and 2012.

		2013				2012
		(In Thousands)
Deferred income tax assets:
Post-retirement benefits		$	90,300			$	151,203
Accrued removal obligation			119,904				105,329
Net operating loss carry forward			42,818				26,775
Other			104,467				58,266
		$	357,489			$	341,573

Deferred income tax liabilities:
Accelerated depreciation timing differences		$	364,321			$	317,885
Plant basis differences			243,629				178,989
Storm regulatory asset			5,883				21,102
Regulatory deferrals related to pension and other post-retirement benefits			110,980				171,576
Investment in GenConn			53,350				52,920
Other			98,126				20,436
		$	876,289			$	762,908

The following table sets forth the carry forward balances for the years ended December 31, 2013 and 2012:

		2013				2012				Year
										Expiration
										Begins
		(In Thousands)
Federal net operating loss		$	122,339			$	76,500				2032
Alternative minimum tax credit			2,697				2,488				N/A
State tax credits			7,289				3,104				2016

SUPPLEMENTARY_INFORMATION

SUPPLEMENTARY INFORMATION	12 Months Ended
SUPPLEMENTARY INFORMATION	Dec. 31, 2013
SUPPLEMENTARY INFORMATION [Abstract]	'
SUPPLEMENTARY INFORMATION	'
	(F) SUPPLEMENTARY INFORMATION

		2013			2012		2011
		(In Thousands)
	Depreciation and Amortization
	Property, plant, and equipment depreciation	$	120,301		$	112,002	$	98,343
	Amortization of nuclear plant regulatory assets		47,476			46,550		44,635
	Amortization of other regulatory assets		22,050			22,745		24,436
	Other		29			51		48
	Total Amortization		69,555			69,346		69,119
	Total Depreciation and Amortization	$	189,856		$	181,348	$	167,462

	Taxes - Other than Income Taxes
	Operating:
	Connecticut gross earnings	$	75,330		$	65,753	$	69,906
	Local real estate and personal property		46,567			40,588		34,902
	Payroll taxes		8,005			7,274		9,373
	Other		556			422		30
	Total Taxes - Other than Income Taxes	$	130,458		$	114,037	$	114,211

	Other Income and (Deductions), net
	Interest income	$	2,733		$	2,631	$	3,483
	Allowance for funds used during construction - equity		10,811			7,480		10,539
	Allowance for funds used during construction - debt		7,170			6,979		9,143
	Weather insurance		(70	)		3,488		3,090
	TSO incentives		-			2,745		-
	Other		(11	)		1,923		677
	Total Other Income and (Deductions), net	$	20,633		$	25,246	$	26,932

PENSION_AND_OTHER_BENEFITS

PENSION AND OTHER BENEFITS	12 Months Ended
PENSION AND OTHER BENEFITS	Dec. 31, 2013
PENSION AND OTHER BENEFITS [Abstract]	'
PENSION AND OTHER BENEFITS	'
	(G) PENSION AND OTHER BENEFITS

	Disclosures pertaining to UIL Holdings’ pension and other postretirement benefit plans (the Plans) are in accordance with ASC 715 “Compensation-Retirement Benefits.” UIL Holdings has an investment policy addressing the oversight and management of pension assets and procedures for monitoring and control. UIL Holdings has engaged State Street Bank as the trustee and investment manager to assist in areas of asset allocation and rebalancing, portfolio strategy implementation, and performance monitoring and evaluation.

	The goals of the asset investment strategy are to:

	·	Achieve long‑term capital growth while maintaining sufficient liquidity to provide for current benefit payments and UIL Holdings’ pension plan operating expenses.
	·	Provide a total return that, over the long term, provides sufficient assets to fund UIL Holdings’ pension plan liabilities subject to an appropriate level of risk, contributions and pension expense.
	·	Optimize the return on assets, over the long term, by investing primarily in a diversified portfolio of equities and additional asset classes with differing rates of return, volatility and correlation.
	·	Diversify investments within asset classes to maximize preservation of principal and minimize over‑exposure to any one investment, thereby minimizing the impact of losses in single investments.

	The Plans seek to maintain compliance with the Employee Retirement Income Security Act of 1974 (ERISA) as amended, and any applicable regulations and laws.

	The Retirement Benefits Plans Investment Committee of the Board of Directors oversees the investment of the Plans’ assets in conjunction with management and has conducted a review of the investment strategies and policies of the Plans. This review included an analysis of the strategic asset allocation, including the relationship of Plan assets to Plan liabilities, and portfolio structure. The 2014 target asset allocations, which may be revised by the Retirement Benefits Plans Investment Committee, are approximately as follows: 50% equity securities, 40% debt securities and 10% other securities, which consist primarily of real assets, hedge funds and high yield securities. In the event that the relationship of Plan assets to Plan liabilities changes, the Retirement Benefits Plans Investment Committee will consider changes to the investment allocations. The other postretirement employee benefit fund assets are invested in a balanced mutual fund and, accordingly, the asset allocation mix of the balanced mutual fund may differ from the target asset allocation mix from time to time.

	The funding policy for the Plans is to make annual contributions that satisfy the minimum funding requirements of ERISA, but that do not exceed the maximum deductible limits of the Internal Revenue Code. These amounts are determined each year as a result of an actuarial valuation of the Plans. UIL Holdings currently expects to make pension contributions of approximately $20 million to $25 million in 2014. Such contribution levels will be adjusted, if necessary, based on final actuarial calculations.

	UIL Holdings applies consistent estimation techniques regarding its actuarial assumptions, where appropriate, across the pension and postretirement plans of its operating subsidiaries. The estimation technique utilized to develop the discount rate for its pension and postretirement benefit plans is based upon the yield of a portfolio of high quality corporate bonds that could be purchased as of December 31, 2013 to produce cash flows matching the expected plan disbursements within reasonable tolerances. The expected return is based upon a combination of historical performance and anticipated future returns for a portfolio reflecting the mix of equity, debt and other investments included in plan assets. Average wage increases are determined from projected annual pay increases, which are used to determine the wage base used to project employees’ pension benefits at retirement. The health care cost trend rate is derived from projections of expected increases in health care costs.

	UIL Holdings is utilizing a discount rate of 5.20% as of December 31, 2013 for all of its qualified pension plans, compared to 4.25% in 2012. The increase in the discount rate, which was due to changes in long-term interest rates, resulted in a decrease to the projected benefit obligation of approximately $100 million from 2012 to 2013. The discount rate for non-qualified pension plans as of December 31, 2013 was 4.9% compared to 4.0% in 2012.

	The discount rate for UIL Holdings’ postretirement benefits plans reflects the differing plan requirements and expected future cash flows. For the UI postretirement plan, the discount rate at December 31, 2013 was 5.20%, compared to 4.25% at December 31, 2012.For the Gas Company postretirement plans, the December 31, 2013 discount rate was a composite rate of 4.85%, weighted by expected future cash outflows, compared to 4.0% for the previous year.

	The pension and other postretirement benefits plans assumptions may be revised over time as economic and market conditions change. Changes in those assumptions could have a material impact on pension and other postretirement expenses. For example, if there had been a 0.25% change in the discount rate assumed for the pension plans, the 2013 pension expense would have increased or decreased inversely by $2.6 million. If there had been a 1% change in the expected return on assets assumed for the pension plans, the 2013 pension expense would have increased or decreased inversely by $6.9 million. If there had been a 0.25% change in the discount rate assumed for the other postretirement benefits plans, the 2013 other postretirement benefits plan expenses would have increased or decreased inversely by $0.3 million. If there had been a 1% change in the expected return on assets assumed for the other postretirement benefits plans, the 2013 other postretirement benefits plan expenses would have increased or decreased inversely by $0.4 million.

	Pension Plans

	The United Illuminating Company Pension Plan (the UI Pension Plan) covers the majority of employees of UIL Holdings Corporate and UI. UI also has a non‑qualified supplemental pension plan for certain employees and a non‑qualified retiree‑only pension plan for certain early retirement benefits.

	The Gas Companies have multiple qualified pension plans covering substantially all of their union and management employees. These entities also have non‑qualified supplemental pension plans for certain employees. The qualified pension plans are traditional defined benefit plans or cash balance plans for those hired on or after specified dates. In some cases, neither of these plans is offered to new employees and have been replaced with enhanced 401(k) plans for those hired on or after specified dates.

	UI has established a supplemental retirement benefit trust and through this trust purchased life insurance policies on certain officers of UIL Holdings and UI to fund the future liability under the non-qualified supplemental plan. The cash surrender value of these policies is included in “Other investments” on the Consolidated Balance Sheet.

	In addition, regarding the non-qualified plans, UIL Holdings has several rabbi trusts which were established to provide a supplemental retirement benefit for certain officers and directors of the Gas Companies.

	Other Postretirement Benefits Plans

	In addition to providing pension benefits, UI also provides other postretirement benefits, consisting principally of health care and life insurance benefits, for retired employees and their dependents. UI does not provide prescription drug benefits for Medicare-eligible employees in its other postretirement health care plans. Non-union employees who are 55 years of age and whose sum of age and years of service at time of retirement is equal to or greater than 65 are eligible for benefits partially subsidized by UI. The amount of benefits subsidized by UI is determined by age and years of service at retirement. For funding purposes, UI established a 401(h) account in connection with the UI Pension Plan and Serial Voluntary Employee Benefit Association Trust (VEBA) accounts for the years 2007 through 2020 to fund other postretirement benefits for UI’s non‑union employees who retire on or after January 1, 1994. These VEBA accounts were approved by the IRS and UI contributed $4.5 million to fund the Serial VEBA accounts in 2007. UI does not expect to make a contribution in 2014 to fund OPEB for non-union employees.

	Union employees whose sum of age and years of service at the time of retirement is equal to or greater than 85 (or who are 62 with at least 20 years of service) are eligible for benefits partially subsidized by UI. The amount of benefits subsidized by UI is determined by age and years of service at retirement. For funding purposes, UI established a VEBA to fund other postretirement benefits for UI’s union employees. The funding strategy for the VEBA is to select funds that most clearly mirror the pension allocation strategy. Approximately 55% of UI’s employees are represented by Local 470‑1, Utility Workers Union of America, AFL‑CIO, for collective bargaining purposes. Plan assets for the union VEBA consist primarily of equity and fixed‑income securities. UI does not expect to make a contribution in 2014 to fund other postretirement benefits for union employees.

	SCG and CNG also have plans providing other postretirement benefits for substantially all of their employees. These benefits consist primarily of health care, prescription drug and life insurance benefits, for retired employees and their dependents. The eligibility for these benefits is determined by the employee’s date of hire, number of years of service, age and whether the employee belongs to a certain group, such as a union. Dependents are also eligible at the employee’s date of retirement provided the retired participant pays the necessary contribution. These plans are contributory with the level of participant’s contributions evaluated annually. Benefits payments under these plans include annual caps for CNG participants hired after 1993 and SCG participants hired after 1996. SCG non-union employees hired after November 1995 are not eligible for these benefits. Union employees hired after April 1, 2010 and December 1, 2009 at SCG and CNG, respectively, are not eligible for these benefits. As such, Gas Company OPEB liabilities are not especially sensitive to increases in the healthcare trend rate. These plans are funded through a combination of 401(h) accounts and Voluntary Employee Benefit Association Trust (VEBA) accounts. UIL Holdings did not make any contributions to these plans in 2013, nor does it currently plan to make a contribution in 2014.

	Other Accounting Matters

	ASC 715 requires an employer that sponsors one or more defined benefit pension or other postretirement plans to recognize an asset or liability for the overfunded or underfunded status of the plan. For a pension plan, the asset or liability is the difference between the fair value of the plan’s assets and the projected benefit obligation. For any other postretirement benefit plan, the asset or liability is the difference between the fair value of the plan’s assets and the accumulated postretirement benefit obligation. UIL Holdings reflects all unrecognized prior service costs and credits and unrecognized actuarial gains and losses as regulatory assets rather than in accumulated other comprehensive income, as management believes it is probable that such items will be recoverable through the ratemaking process. As of December 31, 2013 and 2012, UIL Holdings has recorded regulatory assets of $124.2 million and $264.6 million, respectively.

	In accordance with ASC 715, UIL Holdings utilizes an alternative method to amortize prior service costs and unrecognized gains and losses. UIL Holdings amortizes prior service costs for both the pension and other postretirement benefits plans on a straight-line basis over the average remaining service period of participants expected to receive benefits. UIL Holdings utilizes an alternative method to amortize unrecognized actuarial gains and losses related to the pension and other postretirement benefits plans over the lesser of the average remaining service period or 10 years. For ASC 715 purposes, UIL Holdings does not recognize gains or losses until there is a variance in an amount equal to at least 5% of the greater of the projected benefit obligation or the market-related value of assets. There is no such allowance for a variance in capturing the amortization of other postretirement benefits unrecognized gains and losses.

	The following table represents the change in benefit obligation, change in plan assets and the respective funded status of UIL Holdings’ pension and other postretirement plans as of December 31, 2013 and 2012. Plan assets and obligations have been measured as of December 31, 2013 and 2012.

											Other Post-Retirement
			Pension Benefits								Benefits
			2013				2012				2013				2012
	Change in Benefit Obligation:		(In Thousands)
	Benefit obligation at beginning of year		$	950,608			$	792,101			$	136,687			$	122,382
	Service cost			14,783				12,032				1,923				1,604
	Interest cost			39,948				41,470				5,539				6,246
	Participant contributions			-				-				1,253				1,305
	Settlements (1)			(2,367	)			-				-				-
	Actuarial (gain) loss			(96,739	)			149,088				(13,893	)			12,500
	Benefits paid (including expenses)			(46,971	)			(44,083	)			(11,807	)			(7,350	)
	Benefit obligation at end of year		$	859,262			$	950,608			$	119,702			$	136,687

Change in Plan Assets:
Fair value of plan assets at beginning of year		$	625,061			$	548,122			$	38,540			$	37,573
Actual return on plan assets			54,259				71,595				6,003				4,092
Employer contributions			58,428				49,427				-				-
Participant contributions			-				-				1,253				1,305
Settlements (1)			(2,367	)			-				-				-
Benefits paid (including expenses)			(46,971	)			(44,083	)			(4,633	)			(4,430	)
Fair value of plan assets at end of year		$	688,410			$	625,061			$	41,163			$	38,540

Funded Status at December 31:
Projected benefits (less than) greater than plan assets		$	170,852			$	325,547			$	78,539			$	98,147

Amounts Recognized in the Statement of Financial Position consist of:
Non-current assets		$	-			$	-			$	-			$	-
Current liabilities		$	-			$	-			$	-			$	-
Non-current liabilities		$	170,852			$	325,547			$	78,539			$	98,147

Amounts Recognized as a Regulatory Asset consist of:
Transition obligation (asset)		$	-			$	-			$	-			$	-
Prior service cost			365				859				1,447				45
Net (gain) loss			123,178				244,032				(792	)			19,643
Total recognized as a regulatory asset		$	123,543			$	244,891			$	655			$	19,688

Information on Pension Plans with an Accumulated Benefit Obligation in excess of Plan Assets:
Projected benefit obligation		$	859,262			$	950,608				N/A				N/A
Accumulated benefit obligation		$	784,081			$	858,803				N/A				N/A
Fair value of plan assets		$	688,410			$	625,061				N/A				N/A

The following weighted average actuarial assumptions were used in calculating the benefit obligations at December 31:
Discount rate (Qualified Plans)			5.2	%			4.25	%			N/A				N/A
Discount rate (Non-Qualified Plans)			4.9	%			4	%			N/A				N/A
Discount rate (Other Post-Retirement Benefits)			N/A				N/A				4.85-5.20	%			4.00-4.25	%
Average wage increase			3.50-3.80	%			3.50-3.80	%			N/A				N/A
Health care trend rate (current year)			N/A				N/A				7	%			7.5	%
Health care trend rate (2019-2028 forward)			N/A				N/A				5	%			5	%

(1) Reflects settlement charges resulting from a distribution to a former employee upon retirement
N/A – not applicable

		For the Year Ended December 31,
		Pension Benefits												Other Post-Retirement Benefits
		2013				2012				2011				2013				2012			2011
		(In Thousands)
Components of net periodic benefit cost:
Service cost		$	14,783			$	12,032			$	12,574			$	1,923			$	1,604		$	2,164
Interest cost			39,948				41,470				40,484				5,539				6,246			6,634
Expected return on plan assets			(51,453	)			(44,874	)			(42,588	)			(2,590	)			(2,503	)		(2,965	)
Amortization of:
Prior service costs			605				647				643				(50	)			(69	)		(101	)
Transition obligation (asset)			-				-				-				-				392			1,020
Actuarial (gain) loss			20,829				13,173				14,032				1,776				965			2,008
Settlements (1)			632				-				-				-				-			-
Net periodic benefit cost		$	25,344			$	22,448			$	25,145			$	6,598			$	6,635		$	8,760

Other Changes in Plan Assets and Benefit Obligations Recognized as a Regulatory Asset:
Net (gain) loss		$	(99,572	)		$	122,368			$	34,524			$	(17,257	)		$	10,760		$	(6,608	)
Amortization of:
Current year prior service costs			111				-				-				1,352				-			-
Prior service costs			(605	)			(647	)			(626	)			50				69			101
Transition obligation (asset)			-				-				-				-				(392	)		(1,020	)
Settlements (1)			(632	)			-				-								-			-
Actuarial (gain) loss			(20,829	)			(13,173	)			(14,032	)			(1,776	)			(965	)		(2,008	)
Total recognized as regulatory asset		$	(121,527	)		$	108,548			$	19,866			$	(17,631	)		$	9,472		$	(9,535	)

Total recognized in net periodic benefit costs and regulatory asset		$	(96,183	)		$	130,996			$	45,011			$	(11,033	)		$	16,107		$	(775	)

Estimated Amortizations from Regulatory Assets into Net Periodic Benefit Cost for the next 12 month period:
Amortization of transition obligation		$	-			$	-			$	-			$	-			$	-		$	392
Amortization of prior service cost			291				605				647				284				(50	)		(69	)
Amortization of net (gain) loss			12,386				20,808				13,173				(298	)			1,939			965
Total estimated amortizations		$	12,677			$	21,413			$	13,820			$	(14	)		$	1,889		$	1,288

The following actuarial weighted average assumptions were used in calculating net periodic benefit cost:
Discount rate			4.00-4.25	%			5.05-5.30	%			5.10-5.35	%			4.00-4.25	%			5.05-5.30	%		5.15-5.30	%
Average wage increase			3.50-3.80	%			3.50-3.80	%			3.50-3.80	%			N/A				N/A			N/A
Return on plan assets			7.75-8.00	%			7.75-8.00	%			8.25-8.50	%			5.56-8.00	%			5.56-8.00	%		5.86-8.25	%
Health care trend rate (current year)			N/A				N/A				N/A				7.5	%			8	%		7.80-8.50	%
Health care trend rate (2019 forward)			N/A				N/A				N/A				5	%			5	%		4.50-5.00	%

(1) Reflects settlement charges resulting from a distribution to a former employee upon retirement
N/A – not applicable

A one percentage point change in the assumed health care cost trend rate would have the following effects:

		1% Increase				1% Decrease
		(In Thousands)
Aggregate service and interest cost components		$	751			$	(610	)
Accumulated post-retirement benefit obligation		$	9,559			$	(7,942	)

Estimated Future Benefit Payments

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid:

Year		Pension Benefits				Other
						Postretirement
						Benefits
		(In Thousands)
2014		$	45,266			$	7,447
2015		$	49,699			$	7,710
2016		$	49,437			$	7,763
2017		$	51,358			$	7,892
2018		$	54,013			$	7,969
2019-2022		$	288,030			$	40,009

Defined Contribution Retirement Plans/401(k)

UIL Holdings’ has several 401(k) plans in which substantially all of its employees are eligible to participate. Employees may defer a portion of the compensation and invest in various investment alternatives. Matching contributions are made in the form of UIL Holdings’ common stock or cash and are dependent on the specific provisions of each of the plans. The matching expense for 2013, 2012 and 2011 was $5.2 million, $4.9 million and $4.6 million.

RELATED_PARTY_TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
RELATED PARTY TRANSACTIONS	Dec. 31, 2013
RELATED PARTY TRANSACTIONS [Abstract]	'
RELATED PARTY TRANSACTIONS	'
	(H) RELATED PARTY TRANSACTIONS

	During the years ended December 31, 2013 and 2012, UI received cash distributions from GenConn. See Note (A) “Business Organization and Statement of Accounting Policies – Equity Investments.”

	A Director of UIL Holdings holds a beneficial interest in the building located at 157 Church Street, New Haven, Connecticut, where UIL Holdings leases office space. UIL Holdings’ lease payments for this office space for the years ended December 31, 2013, 2012 and 2011 totaled $1.5 million, $4.8 million and $11.4 million, respectively. The decrease in lease payments in 2013 and 2012 is due to a reduction in office space utilized by UIL Holdings headquarters beginning in June 2012.

	Interest income related to a promissory note from UI to GenConn, which was converted to an equity investment in July 2011, is included in “Other Income and (Deductions), net” in the accompanying Consolidated Statements of Income, in the amount of $1.2 million for the year ended December 31, 2011.

LEASE_OBLIGATIONS

LEASE OBLIGATIONS	12 Months Ended
LEASE OBLIGATIONS	Dec. 31, 2013
LEASE OBLIGATIONS [Abstract]	'
LEASE OBLIGATIONS	'
	(I) LEASE OBLIGATIONS

	UIL Holdings and its wholly-owned direct and indirect subsidiaries have lease arrangements for data processing equipment, office equipment, office space and land.

	Operating leases, which are charged to operating expense, consist principally of leases of office space and facilities, land, railroad rights of way and a wide variety of equipment. The future minimum lease payments under these operating leases are estimated to be as follows:

		(In Thousands)
	2014	$	4,504
	2015		3,576
	2016		3,606
	2017		3,691
	2018		3,537
	2019-after		39,820
		$	58,734

	Rental payments charged to operating expenses in 2013, 2012 and 2011 were as follows:

		Year Ended December 31,
		2013		2012		2011
		(In Thousands)

	Rental payments	$	5,886	$	11,639	$	17,676
	Less: Sublease rental payments received		-		241		1,148
	Rental payments charged to operating expenses	$	5,886	$	11,398	$	16,528

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Dec. 31, 2013
COMMITMENTS AND CONTINGENCIES [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	(J) COMMITMENTS AND CONTINGENCIES

	In the ordinary course of business, UIL Holdings and its subsidiaries are involved in various proceedings, including legal, tax, regulatory and environmental matters, which require management’s assessment to determine the probability of whether a loss will occur and, if probable, an estimate of probable loss. When assessments indicate that it is probable that a liability has been incurred and an amount can be reasonably estimated, UIL Holdings accrues a reserve and discloses the reserve and related matter. UIL Holdings discloses material matters when losses are probable but for which an estimate cannot be reasonably estimated or when losses are not probable but are reasonably possible. Subsequent analysis is performed on a periodic basis to assess the impact of any changes in events or circumstances and any resulting need to adjust existing reserves or record additional reserves. However, given the inherent unpredictability of these legal and regulatory proceedings, we cannot assure you that our assessment of such proceedings will reflect the ultimate outcome, and an adverse outcome in certain matters could have a material adverse effect on our results of operations or cash flows.

	Connecticut Yankee Atomic Power Company

	UI has a 9.5% stock ownership share in the Connecticut Yankee Atomic Power Company (Connecticut Yankee), the carrying value of which was $0.1 million as of December 31, 2013. In 1996, the Board of Directors of Connecticut Yankee voted unanimously to retire the Connecticut Yankee nuclear plant (the Connecticut Yankee Unit) from commercial operation. Connecticut Yankee updates the cost of its remaining decommissioning activity, which consists primarily of groundwater monitoring and nuclear fuel storage, at least annually, and provides UI with a projected schedule depicting annual costs expected to be billed to UI.

	On May 1, 2013, Connecticut Yankee filed an application with FERC to, among other things, reduce its rates and eliminate future decommissioning funding requirements for its owners. On June 27, 2013, FERC issued a final decision which approved both the proposed rate reduction and the elimination of future decommissioning funding requirements.

	As a result, UI’s obligation and corresponding regulatory asset were eliminated at that time. The final decision also allows Connecticut Yankee to distribute the $3.8 million United States Department of Energy (DOE) damage award, discussed below, to its owners and it incorporates Connecticut Yankee’s proposed periodic review mechanism related to the continued adequacy of the Nuclear Decommissioning Trust to meet its financial obligations.

	DOE Spent Fuel Litigation

	The Nuclear Waste Policy Act of 1982 (the Act) requires the DOE to dispose of spent nuclear fuel and other high-level waste (Nuclear Waste) from nuclear generating plants. In 1983, Connecticut Yankee and the DOE entered into a standard disposal contract mandated by the Act which required the DOE to begin disposing of Connecticut Yankee’s Nuclear Waste by the end of January 1998.

	In 1998, Connecticut Yankee filed claims in the United States Court of Federal Claims seeking damages resulting from the breach of the 1983 contracts by the DOE. In September 2010, the court issued its decision and awarded Connecticut Yankee damages of $39.7 million for its spent fuel-related costs through 2001. In May 2012, the United States Court of Appeals affirmed the September 2010 United States Court of Federal Claims award. Connecticut Yankee has received payment of the damage award and, in light of its ownership share, in July 2013 UI received approximately $3.8 million of such award which will be refunded to customers.

	In December 2007, Connecticut Yankee filed a second set of complaints with the United States Court of Federal Claims against the DOE seeking unspecified damages incurred since January 1, 2002 for the DOE’s failure to remove Connecticut Yankee’s spent fuel. In July 2009, Connecticut Yankee provided the DOE with a second set of damage claims totaling approximately $135 million for damages incurred from January 1, 2002 through December 31, 2008. In November 2013, the court issued a decision on the second set of damage claims and awarded Connecticut Yankee damages of $126.3 million. The DOE did not file a notice of appeal. In light of its ownership share, UI expects to receive approximately $12.0 million of such award in the first half of 2014 which would be refunded to customers.

	In August 2013, Connecticut Yankee filed a third set of complaints with the United States Court of Federal Claims against the DOE seeking unspecified damages incurred since January 1, 2009. As an interim measure until the DOE complies with its contractual obligation to dispose of Connecticut Yankee’s spent fuel, Connecticut Yankee constructed an independent spent fuel storage installation (ISFSI), utilizing dry-cask storage, on the site of the Connecticut Yankee Unit and completed the transfer of its Nuclear Waste to the ISFSI in 2005.

	Environmental Matters

	In complying with existing environmental statutes and regulations and further developments in areas of environmental concern, including legislation and studies in the fields of water quality, hazardous waste handling and disposal, toxic substances, climate change and electric and magnetic fields, UIL Holdings and its wholly-owned direct and indirect subsidiaries may incur substantial capital expenditures for equipment modifications and additions, monitoring equipment and recording devices, as well as additional operating expenses. The total amount of these expenditures is not now determinable. Environmental damage claims may also arise from the operations of UIL Holdings’ subsidiaries. Significant environmental issues known to UIL Holdings at this time are described below.

	Site Decontamination, Demolition and Remediation Costs

	In June 2006, UI executed an agreement with the City of Bridgeport and its Redevelopment Authority (the City) to transfer title of UI’s Steel Point property to the City. Pursuant to a Memorandum of Understanding (MOU) among UI, the City, and the City’s selected developer for the property, the City and the developer released UI from any further liability with respect to the Steel Point property after title transferred, and the City and/or the developer has indemnified UI for environmental matters related to the Steel Point property. The Steel Point property includes the land up to the bulkhead. The MOU provides that there is no indemnity for liability related to contaminated harbor sediments, and UI is not aware of any such claims. UI would seek to recover any uninsured costs related to such sediments that are UI’s responsibility, to the extent incurred, through the CTA, in accordance with the ratemaking treatment approved in PURA’s July 2006 decision.

	In 2000, UI conveyed a former generation site on the Mill River in New Haven (English Station) to an unaffiliated entity, Quinnipiac Energy LLC (QE), reserving to UI permanent easements for the operation of its transmission facilities on the site. At the time of the sale, a fund of approximately $1.9 million, an amount equal to the then-current estimate for remediation, was placed in escrow for purposes of bringing soil and groundwater on the English Station site into compliance with applicable environmental laws. As of December 31, 2013, approximately $0.1 million of the escrow fund remained. In 2006, QE sold the property to Evergreen Power, LLC (Evergreen Power) and Asnat Realty LLC (Asnat). In January 2012, Evergreen Power and Asnat filed a lawsuit in federal district court in Connecticut against UI seeking, among other things: (i) an order directing UI to reimburse the plaintiffs for costs they have incurred and will incur for the testing, investigating and remediation of hazardous substances at the English Station site and (ii) an order directing UI to investigate and remediate the site. In May 2012, UI filed an answer and counterclaims. In July 2012, Evergreen Power and Asnat filed a motion for partial summary judgment with respect to UI’s liability under the federal Comprehensive Environmental Response, Compensation, and Liability Act which was denied without prejudice. In December 2013 Evergreen and Asnat filed a subsequent lawsuit in Connecticut state court seeking among other things: (i) remediation of the property; (ii) reimbursement of remediation costs; (iii) termination of UI’s easement rights; (iv) reimbursement for costs associated with securing the property; and (v) punitive damages. UI believes the claims are without merit. UI’s knowledge of the current conditions at the English Station site is insufficient to make a reliable update of the original $1.9 million remediation estimate. Management cannot presently assess the potential financial impact, if any, of the suits, and thus has not recorded a liability related to it and no amount of loss, if any, can be reasonably estimated at this time.

	On April 8, 2013, DEEP issued an administrative order addressed to UI, QE, Evergreen Power, Asnat and others, ordering the parties to take certain actions related to investigating and remediating the English Station site. Mediation of the matter began in the fourth quarter of 2013 and is on-going. At this time, management cannot predict the financial impact on UI of the DEEP order or other matters relating to this site and no amount of loss, if any, can be reasonably estimated at this time.

	In April 1999, UI completed the sale of its Bridgeport Harbor Station and New Haven Harbor Station generating plants in compliance with Connecticut’s electric utility industry restructuring legislation. With respect to the portion of the New Haven Harbor Station site that UI retained, UI has performed an additional environmental analysis, indicating that approximately $3.2 million in remediation expenses will be incurred. Actual remediation costs may be higher or lower than what is currently estimated. The required remediation is virtually all on transmission‑related property and UI has accrued these estimated expenses, which were recovered in transmission rates.

	From 1961 to 1976, UI owned a parcel of property in Derby, Connecticut, on which it operated an oil‑fired electric generating unit. For several years, DEEP has been monitoring and remediating a migration of fuel oil contamination from a neighboring parcel of property into the adjacent Housatonic River. Based on its own investigation to date, UI believes it has no responsibility for this contamination. If regulatory agencies determine that UI is responsible for the cost of these remediation activities, UI may incur substantial costs, no estimate of which is currently available and no amount of loss, if any, can be reasonably estimated at this time.

	The Gas Companies own or have previously owned properties where Manufactured Gas Plants (MGPs) had historically operated. MGP operations have led to contamination of soil and groundwater with petroleum hydrocarbons, benzene and metals, among other things, at these properties, the regulation and cleanup of which is regulated by the federal Resource Conservation and Recovery Act as well as other federal and state statutes and regulations. Each of the Gas Companies has or had an ownership interest in one of such properties contaminated as a result of MGP-related activities. Under the existing regulations, the cleanup of such sites requires state and at times, federal, regulators’ involvement and approval before cleanup can commence. In certain cases, such contamination has been evaluated, characterized and remediated. In other cases, the sites have been evaluated and characterized, but not yet remediated. Finally, at some of these sites, the scope of the contamination has not yet been fully characterized; no liability was recorded in respect of these sites as of December 31, 2013 and no amount of loss, if any, can be reasonably estimated at this time. In the past, the Gas Companies have received approval for the recovery of MGP-related remediation expenses from customers through rates and will seek recovery in rates for ongoing MGP-related remediation expenses for all of their MGP sites.

	SCG owns properties on Housatonic Avenue in Bridgeport, and on Chapel Street in New Haven, and CNG owns a property located on Columbus Boulevard in Hartford, all of which are former MGP sites. Costs associated with the remediation of the sites could be significant and will be subject to a review by PURA as to whether these costs are recoverable in rates. UIL Holdings cannot presently reasonably estimate the costs or range of costs of remediation or the likelihood of recoverability. As a result, as of December 31, 2013, no liabilities related to these properties have been recorded.

	Berkshire owns property on Mill Street in Greenfield, Massachusetts, a former MGP site. UIL Holdings estimates that expenses associated with the remaining remedial activities, as well as the required ongoing monitoring and reporting to the Massachusetts Department of Environmental Protection will most likely amount to $1.2 million and has recorded a liability and offsetting regulatory asset for such expenses as of December 31, 2013. Historically, Berkshire has received approval from the DPU for recovery of environmental expenses in its customer rates. While management cannot at this time reasonably estimate the cost or range of costs of the ongoing and future remediation and monitoring expenses, Berkshire will seek regulatory rate recovery of these expenses.

	Berkshire formerly owned a site on East Street (the East Street Site) in Pittsfield, Massachusetts, a former MGP site. The East Street Site is part of a larger site known as the GE–Pittsfield/Housatonic River Site. Berkshire sold the East Street Site to the General Electric Company (GE) in the 1970s and was named a potentially responsible party by the EPA in 1990. In December 2002, Berkshire reached a settlement with GE (the Settlement Agreement) which provides, among other things, a framework for Berkshire and GE to allocate various monitoring and remediation costs at the East Street Site. As of December 31, 2013, UIL Holdings has accrued approximately $2.9 million and established a regulatory asset for these and future costs incurred by GE in responding to releases of hazardous substances at the East Street Site. Historically, Berkshire has received approval from the DPU for recovery of remediation expenses in its customer rates. While management cannot predict the exact costs of the ongoing and future remediation and monitoring expenses, Berkshire will seek regulatory rate recovery of these expenses.

	Middletown/Norwalk Transmission Project

	The general contractor and two subcontractors responsible for civil construction work in connection with the installation of UI’s portion of the Middletown/Norwalk Transmission Project’s underground electric cable system filed lawsuits in Connecticut state court on September 22, 2009, March 23, 2009 and January 25, 2010, respectively. The claims, as revised by the general contractor in October 2011, sought payment for change order requests of approximately $33.3 million, a 10% general contractor mark-up on any approved subcontractor change order claims (approximately $2.3 million), interest, costs, and attorneys' fees. In December 2011, UI settled claims brought by the two subcontractors and their respective lawsuits were dismissed with prejudice, reducing UI’s estimate of the general contractor’s claims to approximately $7.7 million, exclusive of the contractor’s claims for interest, costs, and attorneys’ fees. UI also is pursuing an indemnification claim against the general contractor for the payments made in settlement to the two subcontractors.

	On September 3, 2013, a Memorandum of Decision was issued by the court finding for UI on all claims but one related to certain change orders, and ordering UI to pay the Contractor approximately $1.3 million. The decision also found against UI on the indemnification claims. On October 22, 2013, the general contractor filed an appeal of the Court’s ruling. UI expects to recover any amounts paid to resolve the contractor and subcontractor claims through UI’s transmission revenue requirements.

	On April 30, 2013, an affiliate of the general contractor for the Middletown/Norwalk Transmission Project, purporting to act as a shareholder on behalf of UIL Holdings, filed a complaint against the UIL Holdings Board of Directors alleging that the directors breached a fiduciary duty by failing to undertake an independent investigation in response to a letter from the affiliate asking for an investigation regarding alleged improper practices by UI in connection with the Middletown/Norwalk Transmission Project. On October 25, 2013, the court granted the defendants’ motion to dismiss the complaint. On November 15, 2013, the plaintiff filed an appeal of the court order in the Connecticut Appellate Court, which remains pending.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
FAIR VALUE MEASUREMENTS	Dec. 31, 2013
FAIR VALUE MEASUREMENTS [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	(K) FAIR VALUE MEASUREMENTS

	As required by ASC 820 “Fair Value Measurements and Disclosures,” financial assets and liabilities are classified in their entirety, based on the lowest level of input that is significant to the fair value measurement. UIL Holdings’ assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels.

	The following tables set forth the fair value of UIL Holdings’ financial assets and liabilities, other than pension benefits and other postretirement benefits as of December 31, 2013 and December 31, 2012.

			Fair Value Measurements Using
			Quoted Prices in				Significant				Significant				Total
			Active Markets				Other				Unobservable
			for Identical				Observable				Inputs (Level 3)
			Assets (Level 1)				Inputs (Level 2)
	31-Dec-13		(In Thousands)
	Assets:
	Derivative assets		$	-			$	-			$	53,447			$	53,447
	Noncurrent investments available for sale			11,148				-				-				11,148
	Deferred Compensation Plan			3,775				-				-				3,775
	Supplemental retirement benefit trust life insurance policies			-				7,898				-				7,898
			$	14,923			$	7,898			$	53,447			$	76,268

	Liabilities:
	Derivative liabilities		$	-			$	-			$	196,233			$	196,233
	Long-term debt			-				1,846,867				-				1,846,867
			$	-			$	1,846,867			$	196,233			$	2,043,100

	Net fair value assets/(liabilities), December 31, 2013		$	14,923			$	(1,838,969	)		$	(142,786	)		$	(1,966,832	)

			Fair Value Measurements Using
			Quoted Prices in				Significant				Significant				Total
			Active Markets				Other				Unobservable
			for Identical				Observable				Inputs (Level 3)
			Assets (Level 1)				Inputs (Level 2)
	31-Dec-12
	Assets:
	Derivative assets		$	-			$	-			$	78,838			$	78,838
	Noncurrent investments available for sale			9,902				-				-				9,902
	Deferred Compensation Plan			3,745				-				-				3,745
	Supplemental retirement benefit trust life insurance policies			-				6,438				-				6,438
			$	13,647			$	6,438			$	78,838			$	98,923

	Liabilities:
	Derivative liabilities		$	-			$	-			$	255,443			$	255,443
	Long-term debt			-				1,886,440				-				1,886,440
			$	-			$	1,886,440			$	255,443			$	2,141,883

	Net fair value assets/(liabilities), December 31, 2011		$	13,647			$	(1,880,002	)		$	(176,605	)		$	(2,042,960	)

	Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The derivative assets consist primarily of CfDs. The determination of fair value of the CfDs was based on a probability-based expected cash flow analysis that was discounted at the December 31, 2013 or December 31, 2012 risk-free interest rates, as applicable, and an adjustment for non-performance risk using credit default swap rates. Certain management assumptions were required, including development of pricing that extended over the term of the contracts. UIL Holdings believes this methodology provides the most reasonable estimates of the amount of future discounted cash flows associated with the CfDs. Additionally, on a quarterly basis, analytics are performed to ensure that the fair value of the derivatives is consistent with changes, if any, in the various fair value model inputs. Additional quantitative information about Level 3 fair value measurements is as follows:

		Unobservable Input		Range

	Contracts for differences	Risk of non-performance			0.00% - 0.62	%
		Discount rate			1.75% - 3.21	%
		Forward pricing ($ per MW)			$1.40 - $9.83

	Significant isolated changes in the risk of non-performance, the discount rate or the contract term pricing would result in an inverse change in the fair value of the CfDs.

	The determination of the fair value of the supplemental retirement benefit trust life insurance policies was based on quoted prices as of December 30, 2013 and December 31, 2012 in the active markets for the various funds within which the assets are held.

	Long-term debt is carried at cost on the consolidated balance sheet. The fair value of long-term debt as displayed in the table above is based on evaluated prices that reflect significant observable market information such as reported trades, actual trade information of similar securities, benchmark yields, broker/dealer quotes of new issue prices and relevant credit information.

	The following tables set forth a reconciliation of changes in the fair value of the assets and liabilities above that are classified as Level 3 in the fair value hierarchy for the twelve month periods ended December 31, 2013 and 2012.

			Year Ended
31-Dec-13
			(In Thousands)

Net derivative assets/(liabilities), December 31, 2012		$	(176,605	)
Unrealized gains and (losses), net
Included in earnings			-
Included in regulatory assets/(liabilities)			33,819
Settlements			-
Net derivative assets/(liabilities), December 31, 2013		$	(142,786	)

Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of December 31, 2013		$	33,819

		Year Ended
		31-Dec-12
		(In Thousands)

Net derivative assets/(liabilities), December 31, 2011		$	(180,581	)
Unrealized gains and (losses), net
Included in earnings			3,488
Included in regulatory assets/(liabilities)			7,488
Settlements			(7,000	)
Net derivative assets/(liabilities), December 31, 2012		$	(176,605	)

Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of December 31, 2012		$	7,488

The following table sets forth a reconciliation of changes in the net regulatory asset/(liability) balances that were established to recover any unrealized gains/(losses) associated with the CfDs for the years ended December 31, 2013 and 2012. The amounts offset the net CfDs liabilities included in the derivative liabilities detailed above.

		Year Ended
		31-Dec-13
		(In Thousands)

Net regulatory assets/(liabilities), December 31, 2012		$	176,605
Unrealized (gains) and losses, net			(33,819	)
Net regulatory assets/(liabilities), December 31, 2013		$	142,786

		Year Ended
		31-Dec-12
		(In Thousands)

Net regulatory assets/(liabilities), December 31, 2011		$	184,093
Unrealized (gains) and losses, net			(7,488	)
Net regulatory assets/(liabilities), December 31, 2012		$	176,605

The following tables set forth the fair values of UIL Holdings’ pension and OPEB assets as of December 31, 2013 and 2012.

		Fair Value Measurements Using
		Quoted Prices in				Significant				Significant				Total
		Active Markets for				Other				Unobservable
		Identical Assets				Observable				Inputs (Level 3)
		(Level 1)				Inputs (Level 2)
		(In Thousands)
31-Dec-13

Pension assets
Cash and cash equivalents		$	-			$	-			$	-			$	-
Mutual funds			-				653,579				-				653,579
Hedge fund			-				-				34,831				34,831
			-				653,579				34,831				688,410
OPEB assets
Mutual funds			41,163				-				-				41,163
			41,163				-				-				41,163

Fair value of plan assets, December 31, 2013		$	41,163			$	653,579			$	34,831			$	729,573

31-Dec-12

Pension assets
Cash and cash equivalents		$	1,606			$	-			$	-			$	1,606
Mutual funds			-				595,772				-				595,772
Hedge fund			-				-				27,683				27,683
			1,606				595,772				27,683				625,061
OPEB assets
Mutual funds			38,540				-				-				38,540
			38,540				-				-				38,540

Fair value of plan assets, December 31, 2012		$	40,146			$	595,772			$	27,683			$	663,601

The determination of fair values of the Level 2 co-mingled mutual funds and the Level 3 hedge fund were based on the Net Asset Value (NAV) provided by the managers of the underlying fund investments and the unrealized gains and losses. The NAV provided by the managers typically reflect the fair value of each underlying fund investment. Changes in the fair value of pension benefits and OPEB are accounted for in accordance with ASC 715 Compensation – Retirement Benefits as discussed in Note (G) “Pension and Other Benefits”.

The following tables set forth a reconciliation of changes in the fair value of the assets above that are classified as Level 3 in the fair value hierarchy for the twelve month periods ended December 31, 2013 and 2012.

		Year Ended
		31-Dec-13
		(In Thousands)
Pension assets-Level 3, December 31, 2012		$	27,683
Unrealized/Realized gains and (losses), net			2,035
Purchases			5,113
Pension assets-Level 3, December 31, 2013		$	34,831

		Year Ended
		31-Dec-12
		(In Thousands)
Pension assets-Level 3, December 31, 2011		$	-
Unrealized/Realized gains and (losses), net			479
Purchases			27,204
Pension assets-Level 3, December 31, 2012		$	27,683

QUARTERLY_FINANCIAL_DATA_UNAUD

QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
QUARTERLY FINANCIAL DATA (UNAUDITED)	Dec. 31, 2013
QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]	'
QUARTERLY FINANCIAL DATA (UNAUDITED)	'
	(L) QUARTERLY FINANCIAL DATA (UNAUDITED)

	Selected quarterly financial data for 2013 and 2012 are set forth below:

			1^st		2^nd		3rd		4^th
			Quarter		Quarter		Quarter		Quarter
	(In Thousands, Except Per Share Amounts)
	2013
	Operating Revenues		$	548,039	$	319,074	$	316,478	$	435,125
	Operating Income		$	96,233	$	43,235	$	22,659	$	78,362
	Net Income		$	51,807	$	17,934	$	5,157	$	40,419
	Net Income attributable to UIL Holdings		$	51,791	$	17,924	$	5,144	$	40,406

	Earnings Per Share of Common Stock – Basic: (1)		$	1.02	$	0.35	$	0.1	$	0.71

	Earnings Per Share of Common Stock – Diluted: (1)		$	1.01	$	0.35	$	0.1	$	0.71

	2012
	Operating Revenues		$	457,818	$	282,842	$	322,888	$	422,953
	Operating Income		$	87,461	$	36,507	$	39,126	$	67,496
	Net Income		$	47,076	$	12,012	$	15,775	$	28,838
	Net Income attributable to UIL Holdings		$	47,050	$	11,999	$	15,749	$	28,839

	Earnings Per Share of Common Stock – Basic: (1)		$	0.93	$	0.24	$	0.31	$	0.57

	Earnings Per Share of Common Stock – Diluted: (1)		$	0.92	$	0.23	$	0.31	$	0.56

	-1	Based on weighted average number of shares outstanding each quarter. Diluted earnings per share reflects the effect of dilutive stock options, performance shares and restricted stock. Quarterly per share amounts are not intended to be additive.

SEGMENT_INFORMATION

SEGMENT INFORMATION	12 Months Ended
SEGMENT INFORMATION	Dec. 31, 2013
SEGMENT INFORMATION [Abstract]	'
SEGMENT INFORMATION	'
	(M) SEGMENT INFORMATION

	UIL Holdings is organized into Electric Distribution, Electric Transmission and Gas Distribution reporting segments based on several factors including, but not limited to, the nature of each segment’s products and services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates. The following measures of segment profit and loss are utilized by management to make decisions about allocating resources to the segments and assessing performance. The following table reconciles certain segment information with that provided in UIL Holdings’ Consolidated Financial Statements. In the table, distribution includes all electric utility revenue and expenses except for transmission, which is provided in a separate column. “Other” includes the information for the remainder of UIL Holdings’ non‑utility activities and unallocated corporate costs, including minority interest investments and administrative costs. Revenues from inter‑segment transactions are not material. All of UIL Holdings’ revenues are derived in the United States.

	(In Thousands)
			31-Dec-13
			Electric Distribution and Transmission
			Distribution			Transmission			Total			Gas Distribution				Other				Total
	Operating Revenues		$	560,877		$	242,681		$	803,558		$	815,023			$	135			$	1,618,716
	Purchased power and gas			139,135			-			139,135			438,189				-				577,324
	Operation and maintenance			189,378			45,540			234,918			154,418				(5,307	)			384,029
	Transmission wholesale			-			88,206			88,206			-				-				88,206
	Depreciation and amortization			91,670			16,353			108,023			77,890				3,943				189,856
	Taxes - other than income taxes			49,421			33,991			83,412			46,477				569				130,458
	Regulatory disallowances			8,354			-			8,354			-				-				8,354
	Operating Income			82,919			58,591			141,510			98,049				930				240,489

	Other Income and (Deductions), net			13,335			4,874			18,209			(323	)			2,747				20,633

	Interest Charges, net			27,052			12,046			39,098			28,935				23,736				91,769

	Income from Equity Investments			15,272			-			15,272			-				-				15,272

	Income (Loss) Before Income Taxes			84,474			51,419			135,893			68,791				(20,059	)			184,625

	Income Taxes			37,816			17,784			55,600			23,309				(9,601	)			69,308
	Net Income (Loss)			46,658			33,635			80,293			45,482				(10,458	)			115,317
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			52				-				52
	Net Income (Loss) attributable to UIL Holdings		$	46,658		$	33,635		$	80,293		$	45,430			$	(10,458	)		$	115,265

	Total Capital Expenditures (1)		$	-		$	-		$	160,042		$	97,346			$	47,790			$	305,178

			Electric Distribution and Transmission (2)
			Distribution			Transmission			Total			Gas Distribution (3)				Other				Total
	Total Assets at December 31, 2013		$	-		$	-		$	2,950,707		$	2,010,246			$	183,267			$	5,144,220

	-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
	-2	Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2013, was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.
	-3	Includes $266.2 million of goodwill in the Gas Distribution segment as of December 31, 2013.

	(In Thousands)
			31-Dec-12
			Electric Distribution and Transmission
			Distribution			Transmission			Total			Gas Distribution				Other				Total
	Operating Revenues		$	561,148		$	222,314		$	783,462		$	702,887			$	152			$	1,486,501
	Purchased power and gas			154,546			-			154,546			370,234				-				524,780
	Operation and maintenance			178,862			43,185			222,047			137,707				(3,477	)			356,277
	Transmission wholesale			-			79,469			79,469			-				-				79,469
	Depreciation and amortization			88,672			14,890			103,562			75,205				2,581				181,348
	Taxes - other than income taxes			44,845			26,773			71,618			42,254				165				114,037
	Operating Income			94,223			57,997			152,220			77,487				883				230,590

	Other Income and (Deductions), net			16,562			3,945			20,507			4,071				668				25,246

	Interest Charges, net			28,308			12,941			41,249			28,001				23,292				92,542

	Income from Equity Investments			15,273			-			15,273			-				-				15,273

	Income (Loss) Before Income Taxes			97,750			49,001			146,751			53,557				(21,741	)			178,567

	Income Taxes			45,091			17,025			62,116			21,305				(8,555	)			74,866
	Net Income (Loss)			52,659			31,976			84,635			32,252				(13,186	)			103,701
Less:
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			64				-				64
Net Income (Loss) attributable to UIL Holdings		$	52,659		$	31,976		$	84,635		$	32,188			$	(13,186	)		$	103,637

Total Capital Expenditures (1)		$	-		$	-		$	178,107		$	80,837			$	29,689			$	288,633

		Electric Distribution and Transmission (2)
		Distribution			Transmission			Total			Gas Distribution (3)				Other				Total (3)
Total Assets at December 31, 2012		$	-		$	-		$	2,935,562		$	1,993,560			$	90,042			$	5,019,164

		31-Dec-11
		Electric Distribution and Transmission
		Distribution			Transmission			Total			Gas Distribution				Other				Total
Operating Revenues		$	599,153		$	198,503		$	797,656		$	772,315			$	123			$	1,570,094
Purchased power and gas			180,149			-			180,149			429,079				-				609,228
Operation and maintenance			216,361			32,027			248,388			133,126				300				381,814
Transmission wholesale			-			77,997			77,997			-				-				77,997
Depreciation and amortization			83,725			12,690			96,415			70,694				353				167,462
Taxes - other than income taxes			45,967			24,736			70,703			43,494				14				114,211
Operating Income (Loss)			72,951			51,053			124,004			95,922				(544	)			219,382

Other Income and (Deductions), net			14,697			6,651			21,348			6,571				(987	)			26,932

Interest Charges, net			30,489			13,235			43,724			28,939				22,722				95,385

Income from Equity Investments			11,282			-			11,282			-				-				11,282

Income (Loss) Before Income Taxes			68,441			44,469			112,910			73,554				(24,253	)			162,211
Income Taxes			30,865			13,186			44,051			29,721				(11,271	)			62,501
Net Income (Loss)			37,576			31,283			68,859			43,833				(12,982	)			99,710
Less:
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			54				-				54
Net Income (Loss) attributable to UIL Holdings		$	37,576		$	31,283		$	68,859		$	43,779			$	(12,982	)		$	99,656

Total Capital Expenditures (1)		$	-		$	-		$	247,563		$	60,349			$	20,167			$	328,079

		Electric Distribution and Transmission (2)
		Distribution			Transmission			Total			Gas Distribution (3)				Other				Total (3)
Total Assets at December 31, 2011		$	-		$	-		$	2,716,460		$	1,953,079			$	75,070			$	4,744,609

-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
-2	Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2012, was $1,114.2 million and $612.0 million for Distribution and Transmission, respectively. As of December 31, 2011, net plant in service was $1,029.8 million and $495.8 million for Distribution and Transmission, respectively.
-3	Includes $266.8 million of goodwill in the Gas Distribution segment as of December 31, 2012 and 2011.

Schedule_I_Condensed_Financial

Schedule I - Condensed Financial Statements of Registrant	12 Months Ended
Schedule I - Condensed Financial Statements of Registrant	Dec. 31, 2013
Schedule I - Condensed Financial Statements of Registrant	'
Schedule I - Condensed Financial Statements of Registrant	'
	Schedule I – Condensed Financial Statements of Registrant

	UIL HOLDINGS CORPORATION (PARENT)
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	STATEMENTS OF INCOME
	FOR THE YEARS ENDED DECEMBER 31, 2013, 2012, AND 2011
	(In Thousands except per share amounts)

			2013				2012				2011

	Operating Revenues		$	6,209			$	4,193			$	353

	Operating Expenses
	Operation and maintenance			844				639				548
	Depreciation and amortization			3,842				2,530				306
	Taxes - other than income taxes			562				156				10
	Total Operating Expenses			5,248				3,325				864
	Operating Income			961				868				(511	)

	Other Income and (Deductions), net			2,552				351				(1,609	)

	Interest Charges, net			23,735				23,292				22,784

	Equity in earnings of subsidiaries			125,871				117,083				113,081

	Income Before Income Taxes			105,649				95,010				88,177

	Income Taxes			(9,668	)			(8,691	)			(11,533	)

	Net Income			115,317				103,701				99,710
	Net Income Attributable to Noncontrolling Interest			52				64				54
	Net Income Attributable to UIL Holdings		$	115,265			$	103,637			$	99,656

	Average Number of Common Shares Outstanding - Basic			52,415				50,831				50,609
	Average Number of Common Shares Outstanding - Diluted			52,711				51,108				50,926

	Earnings Per Share of Common Stock - Basic:		$	2.2			$	2.04			$	1.96

	Earnings Per Share of Common Stock - Diluted:		$	2.18			$	2.02			$	1.95

	UIL HOLDINGS CORPORATION (PARENT)
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	STATEMENTS OF COMPREHENSIVE INCOME
	FOR THE YEARS ENDED DECEMBER 31, 2013, 2012, AND 2011
	(In Thousands)

			2013				2012				2011

	Net Income		$	115,317			$	103,701			$	99,710
	Other Comprehensive Income (Loss), net of deferred income taxes
	Changes in unrealized gains(losses) related to pension and other post-retirement benefit plans			1,008				(90	)			(576	)
	Other			(24	)			16				35
	Total Other Comprehensive Income (Loss), net of deferred income taxes			984				(74	)			(541	)
	Comprehensive Income			116,301				103,627				99,169
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			52				64				54
	Comprehensive Income Attributable to UIL Holdings		$	116,249			$	103,563			$	99,115

	UIL HOLDINGS CORPORATION (PARENT)
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	BALANCE SHEET
	AS OF DECEMBER 31, 2013 AND 2012
	(In Thousands)

		December 31,				December 31,
		2013				2012

ASSETS
Current Assets
Unrestricted cash and temporary cash investments		$	28,915			$	115
Intercompany receivable			22,934				3,264
Deferred income taxes			19,927				2,145
Refundable taxes			13,337				24,101
Other			5,720				4,553
Total Current Assets			90,833				34,178

Investments in Subsidiaries			1,668,558				1,689,917

Net Property, Plant and Equipment			105,078				60,588

Other Assets			6,520				6,095

Total Assets		$	1,870,989			$	1,790,778

LIABILITIES AND CAPITALIZATION
Current Liabilities
Line of credit borrowings		$	-			$	157,000
Accounts payable			15,780				22,242
Dividends payable			24,392				21,887
Other			23,500				21,079
Total Current Liabilities			63,672				222,208

Deferred income taxes			1,035				-
Other Liabilities			5,558				4,934

Capitalization
Long-term debt, net of unamortized discount and premium			447,403				447,083

Net Common Stock Equity			1,353,321				1,116,553

Total Capitalization			1,800,724				1,563,636

Total Liabilities and Capitalization		$	1,870,989			$	1,790,778

UIL HOLDINGS CORPORATION (PARENT)
CONDENSED FINANCIAL INFORMATION OF REGISTRANT
STATEMENTS OF CASH FLOWS
FOR THE YEARS ENDED DECEMBER 31, 2013, 2012, AND 2011
(In Thousands)

		2013				2012				2011

Net Cash provided by Operating Activities		$	122,285			$	89,875			$	162,538

Cash Flows from Investing Activities
Acquisition of Gas Companies			-				-				11,211
Plant expenditures			(47,790	)			(29,689	)			(20,168	)
Capital contributions to subsidiaries			-				(100,000	)			(60,000	)
Intercompany loan receivable			(8,000	)			-				-
Other			-				304				18
Net Cash (used in) Investing Activities			(55,790	)			(129,385	)			(68,939	)

Cash Flows from Financing Activities
Issuance of common stock			206,516				1,943				200
Payments on long-term debt			-				-				(49,286	)
Line of credit borrowings (repayments), net			(157,000	)			122,000				35,000
Payment of common stock dividend			(87,602	)			(87,490	)			(87,274	)
Other			391				508				(107	)
Net Cash provided by (used in) Financing Activities			(37,695	)			36,961				(101,467	)

Unrestricted Cash and Temporary Cash Investments:
Net change for the period			28,800				(2,549	)			(7,868	)
Balance at beginning of period			115				2,664				10,532
Balance at end of period		$	28,915			$	115			$	2,664

Note 1. Basis of Presentation

The accompanying condensed financial statements of UIL Holdings Corporation (parent) should be read in conjunction with the consolidated financial statements and notes thereto of UIL Holdings Corporation and subsidiaries ("Registrant") included in Part II, Item 8 of this Form 10-K. UIL Holdings Corporation’s (parent) significant accounting policies are consistent with those of the Registrant.

Dividends Paid

UIL Holdings Corporation received dividend from subsidiaries of $140.5 million, $73.1 million and $174.5 million in 2013, 2012 and 2011, respectively.

Note 2. Capitalization and Short-Term Credit Arrangements

See Notes to Consolidated Financial Statements in this Form 10-K for disclosure of Parent’s capitalization information as described in Note B “Capitalization” and of line of credit borrowings as described in Note D “Short-Term Credit Arrangements.”

Information regarding maturities of long-term debt are set forth below:

		2014				2015				2016				2017		2018 &
		2014				2015				2016				2017		thereafter
(In Thousands)
Maturities		$	-			$	-			$	-			$	-	$	450,000

Note 3. Related Party Transactions

Parent revenues from services provided to its subsidiaries are shown as operating revenues in the accompanying statements of income. Intercompany Accounts Receivables and Payables at December 31, 2013 and 2012 are not material.

Note 4. Contingencies

For a discussion of material contingencies see “Item 8. Notes to Consolidating Financial Statements – Note J Commitments and Contingencies” in this Form 10-K.

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
Schedule II - Valuation and Qualifying Accounts	Dec. 31, 2013
Schedule II-Valuation and Qualifying Accounts [Abstract]	'
Schedule II-Valuation and Qualifying Accounts	'
	UIL Holdings Corporation
	Schedule II - Valuation and Qualifying Accounts
	For the Years Ended December 31, 2013, 2012 and 2011
	(Thousands of Dollars)

	Col. A.	Col. B.		Col. C.		Col. D.				Col. E.			Col. F.
						Additions
		Balance at				Charged to		Charged to					Balance at
		Beginning		Acquired		Costs and		Other					End
	Classification	of Period		Balance		Expenses		Accounts		Deductions			of Period

	RESERVE DEDUCTION FROM ASSETS TO WHICH IT APPLIES:

	Reserve for uncollectible accounts (consolidated):
	2013	$	11,867	$	-	$	33,476	$	-	$	33,322	(A)	$	12,021
	2012	$	10,939	$	-	$	36,850	$	-	$	35,922	(A)	$	11,867
	2011	$	10,571	$	-	$	32,829	$	-	$	32,461	(A)	$	10,939

	(A) Accounts written off, net of recoveries

STATEMENT_OF_ACCOUNTING_POLICI1

STATEMENT OF ACCOUNTING POLICIES (Policies)	12 Months Ended
STATEMENT OF ACCOUNTING POLICIES (Policies)	Dec. 31, 2013
STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
Basis of Presentation	'
	Basis of Presentation

	The financial statements of UIL Holdings are prepared on a consolidated basis and therefore include the accounts of UIL Holdings’ majority-owned subsidiaries noted above. Intercompany accounts and transactions have been eliminated in consolidation.

	The preparation of financial statements in conformity with GAAP requires management to use estimates and assumptions that affect (1) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and (2) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

	The Company has revised its previously issued annual financial statements to correct an error in the 2012 Consolidated Balance Sheet. The effect of this revision is a $59.8 million adjustment increasing net property, plant and equipment and increasing non-current regulatory liabilities in the Consolidated Balance Sheet as of December 31, 2012. The Company has also revised the 2012 Consolidated Balance sheet for an adjustment, the effect of which is a $13.1 million adjustment increasing accounts payable and decreasing accrued liabilities in the Consolidated Balance Sheet as of December 31, 2012. These adjustments are not considered to be material individually or in the aggregate to previously issued financial statements. These adjustments did not have an impact on the Consolidated Statements of Income, Comprehensive Income, Cash Flows and Changes in Stockholders' Equity. Additionally certain immaterial amounts that were reported as such in the Consolidated Financial Statements in previous periods have been reclassified to conform to the current presentation.
Allowance for Funds Used During Construction	'
	Allowance for Funds Used During Construction

	In accordance with the uniform systems of accounts, the Company capitalizes allowance for funds used during construction (AFUDC) , which represents the approximate cost of debt and equity capital devoted to plant under construction. The portion of the allowance applicable to borrowed funds and the allowance applicable to equity funds are presented as other income in the Consolidated Statement of Income. Although the allowance does not represent current cash income, it has been recoverable under the ratemaking process over the service lives of the related properties. Weighted-average AFUDC rates for 2013, 2012 and 2011 were 9.63%, 5.61% and 5.75%, respectively.
Asset Retirement Obligations	'
	Asset Retirement Obligations

	The fair value of the liability for an asset retirement obligation (ARO) and/or a conditional ARO is recorded in the period in which it is incurred and the cost is capitalized by increasing the carrying amount of the related long-lived asset. The liability is adjusted to its present value periodically over time, and the capitalized cost is depreciated over the useful life of the related asset. Upon settlement, the obligation is settled either at its recorded amount or a gain or a loss is incurred.

	Any timing differences between rate recovery and depreciation expense are deferred as either a regulatory asset or a regulatory liability.

	The term conditional ARO refers to an entity's legal obligation to perform an asset retirement activity in which the timing and/or method of settlement are conditional on a future event that may or may not be within the control of the entity. If an entity has sufficient information to reasonably estimate the fair value of the liability for a conditional ARO, it must recognize that liability at the time the liability is incurred.

	As of December 31, 2013 and 2012, UIL Holdings’ ARO, including estimated conditional AROs, was $18.5 million and $18.3 million, respectively, and consisted primarily of obligations related to the removal or retirement of asbestos, polychlorinated biphenyl (PCB)-contaminated equipment, gas pipeline and cast iron gas mains. The long-lived assets associated with the AROs are gas storage property, distribution property and other property. UIL Holdings’ ARO is carried on the balance sheet as other long-term liabilities.

	ARO activity for 2013 and 2012 is as follows:

			2013			2012
			(In Thousands)
	Balance as of December 31		$	18,289		$	18,058
	Liabilities incurred during the year			-			-
	Liabilities settled during the year			(740	)		(718	)
	Accretion			961			949
	Balance as of December 31		$	18,510		$	18,289
Cash and Temporary Cash Investments	'
	Cash and Temporary Cash Investments

	UIL Holdings considers all of its highly liquid debt instruments with an original maturity of three months or less at the date of purchase to be cash and temporary cash investments.
Depreciation	'
	Depreciation

	Provisions for depreciation on utility plant for book purposes are computed on a straight‑line basis, using estimated service lives. For utility plant other than software, service lives are determined by independent engineers and subject to review and approval by PURA and DPU. Software service life is based upon management’s estimate of useful life. The aggregate annual provisions for depreciation for the years 2013, 2012 and 2011 were approximately 3.4%, 3.5%, and 3.3%, respectively, of the original cost of depreciable property.
Derivatives	'
	Derivatives

	UIL Holdings’ regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives. The values of the gross derivative assets and liabilities as of December 31, 2013 and 2012 were as follows:

			December 31,			December 31,
			2013			2012
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,098		$	12,671
	Deferred Charges and Other Assets		$	44,349		$	67,167

	Gross derivative liabilties:
	Current Liabilities		$	26,976		$	30,804
	Noncurrent Liabilities		$	169,327		$	224,639

	Contracts for Differences (CfDs)
	Pursuant to Connecticut’s 2005 Energy Independence Act, the Connecticut Public Utilities Regulatory Authority (PURA) solicited bids to create new or incremental capacity resources in order to reduce federally mandated congestion charges, and selected four new capacity resources. To facilitate the transactions between the selected capacity resources and Connecticut electric customers, and provide the commitment necessary for owners of these resources to obtain necessary financing, PURA required that UI and The Connecticut Light and Power Company (CL&P) execute long-term contracts with the selected resources. In August 2007, PURA approved four CfDs, each of which specifies a capacity quantity and a monthly settlement that reflects the difference between a forward market price and the contract price. UI executed two of the contracts and CL&P executed the other two contracts. The costs or benefits of each contract will be paid by or allocated to customers and will be subject to a cost-sharing agreement whereby approximately 20% of the cost or benefit is borne by or allocated to UI customers and approximately 80% is borne by or allocated to CL&P customers.
	PURA has determined that costs associated with these CfDs will be recoverable by UI and CL&P, and in accordance with ASC 980 “Regulated Operations,” UI has deferred recognition of costs (a regulatory asset) or obligations (a regulatory liability). The CfDs are marked-to-market in accordance with ASC 815 “Derivatives and Hedging.” For those CfDs signed by CL&P, UI records its approximate 20% portion pursuant to the cost-sharing agreement noted above. As of December 31, 2013, UI has recorded a gross derivative asset of $53.4 million, a regulatory asset of $142.7 million, and a gross derivative liability of $196.2 million ($129.4 million of which is related to UI’s portion of CL&P’s derivative liabilities). See Note (K) “Fair Value of Financial Instruments” for additional CfD information.
	The unrealized gains and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for years ended December 31, 2013 and 2012 were as follows:

			Year Ended
			December 31,
			2013			2012
			(In Thousands)

	Regulatory Assets - Derivative liabilities		$	(33,819	)	$	(7,500	)

	Regulatory Liabilities - Derivative assets		$	-		$	12

	The increase in unrealized losses in the year ended December 31, 2013 compared to 2012 is due to increases in forward pricing.

	Weather Insurance Contracts

	On an annual basis, the Gas Companies each assess the need for weather insurance contracts for the upcoming heating season in order to provide financial protection from significant weather fluctuations. According to the terms of such contracts, if temperatures are warmer than normal at a prescribed level for the contract period, a payment is received by the gas company; in addition, under certain of the contracts, if temperatures are colder than normal at a prescribed level for the contract period, the gas company is required to make a payment. The premiums paid are amortized over the terms of the contracts. The intrinsic value of the contracts is carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).

	In October of 2013, CNG entered into a weather insurance contract for the period of November 1, 2013 through December 31, 2013. If temperatures were warmer than normal, CNG would receive a payment, up to a maximum of $1.5 million; however, if temperatures were colder than normal, CNG would make a payment of up to a maximum of $1 million. As a result of PURA’s approval for a decoupling mechanism which went into effect on January 10, 2014, the contract did not extend into the 2014 portion of the heating season. The intrinsic value of the contract, which is carried on the balance sheet as a derivative liability, totaled $0.1 million at December 31, 2013, and was subsequently paid.

	In October 2013, Berkshire entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014. If temperatures are warmer than normal, Berkshire will receive a payment, up to a maximum of $1 million; however, if temperatures are colder than normal, Berkshire will make a payment of up to a maximum of $0.2 million. The contract had no value at December 31, 2013 since the variation from normal weather through December 31, 2013 did not reach the prescribed level stated in the contract.

	In September 2013, SCG entered into a weather insurance contract for the winter period of November 1, 2013 through April 30, 2014. If temperatures are warmer than normal, SCG will receive a payment, up to a maximum of $3 million; however, if temperatures are colder than normal, SCG will make a payment of up to a maximum of $2 million. The contract had no value at December 31, 2013 since the variation from normal weather through December 31, 2013 did not reach the prescribed level stated in the contract.

	In October 2012, SCG and CNG each entered into weather insurance contracts for the winter period of November 1, 2012 through April 30, 2013. If temperatures were warmer than normal, SCG and CNG each would have received a payment, up to a maximum of $3 million; however, if temperatures were colder than normal, SCG and CNG each would have made a payment of up to a maximum of $2 million. Upon the expiration of their respective contracts, SCG and CNG neither received nor made a payment since the variation from normal weather during the contract period did not reach the prescribed level stated in the contracts.

	In November 2011, Berkshire entered into a weather insurance contract for calendar year 2012. According to the terms of the contract, because temperatures were warmer than normal for the contract period, Berkshire received a payment of $1 million on January 8, 2013. The premiums paid were amortized over the term of the contract. The intrinsic value of the contract, $1 million at December 31, 2012, was carried on the balance sheet with changes in value recorded in the income statement as Other Income and (Deductions).
Earnings per share	'
	Earnings per Share

	The following table presents a reconciliation of the basic and diluted earnings per share calculations for the years 2013, 2012 and 2011:


			Year Ended December 31,
			2013			2012			2011
			(In Thousands, except per share amounts)

	Numerator:
	Net income attributable to UIL Holdings		$	115,265		$	103,637		$	99,656
	Less: Net income allocated to unvested units			117			184			210
	Net income attributable to common shareholders		$	115,148		$	103,453		$	99,446

	Denominator:
	Basic average number of shares outstanding			52,415			50,831			50,609
	Effect of dilutive securities			296			277			317
	Diluted average number of shares outstanding			52,711			51,108			50,926

	Earnings per share:
	Basic		$	2.2		$	2.04		$	1.96
	Diluted		$	2.18		$	2.02		$	1.95

	All outstanding options to purchase shares of common stock during 2013 and 2012 were included in the computation of diluted earnings per share because the options’ exercise prices were lower than the average market price of the common shares during such period. Options to purchase 89,336 shares of common stock were outstanding during 2011 but were not included in the computation of diluted earnings per share because the options’ exercise prices were greater than the average market price of the common shares during such period.
Equity Investments	'
	Equity Investments

	UI is party to a 50-50 joint venture with NRG affiliates in GenConn, which operates two peaking generation plants in Connecticut. UI’s investment in GenConn is being accounted for as an equity investment, the carrying value of which was $118.2 million and $124.8 million as of December 31, 2013 and 2012, respectively. As of December 31, 2013, there were approximately $0.1 million of undistributed earnings from UI’s equity investment in GenConn.

	UI’s pre-tax income from its equity investment in GenConn was $15.3 million, $15.3 million and $11.3 million for the years ended December 31, 2013, 2012 and 2011, respectively.

	Cash distributions from GenConn are reflected as either distributions of earnings or as returns of capital in the operating and investing sections of the Consolidated Statement of Cash Flows, respectively. During the years ended December 31, 2013, 2012 and 2011, UI received cash distributions from GenConn of approximately $21.8 million, $21.5 million and $8.0 million.
Goodwill	'
	Goodwill

	UIL Holdings may be required to recognize an impairment of goodwill in the future due to market conditions or other factors related to its results of operations and performance. Those market events could include a decline in the forecasted results in the company business plan, significant adverse rate case results, changes in capital investment budgets or changes in interest rates that could impair the fair value of a reporting unit. Recognition of impairments of a significant portion of goodwill would negatively affect reported results of operations and total capitalization, the effect of which could be material and could make it more difficult to maintain credit ratings, secure financing on attractive terms, maintain compliance with debt covenants and meet expectations of regulators.

	A goodwill impairment test is performed each year and the test will be updated between annual tests if events or circumstances occur that may reduce the fair value of a reporting unit below its carrying value. The annual analysis of the potential impairment of goodwill is a two-step process. Step one of the impairment test consists of comparing the fair values of reporting units with their aggregate carrying values, including goodwill. The estimated fair values for the reporting units are determined by using the income approach and the market approach methodologies.

	The income approach is based on discounted cash flows which are derived from internal forecasts and economic expectations. Key assumptions used to determine fair value under the income approach include the cash flow period, terminal values based on a terminal growth rate, and the discount rate. The discount rate represents the estimated cost of debt and equity financing weighted by the percentage of debt and equity in a company's target capital structure.

	The market approach utilizes the guideline company method, which calculates valuation multiples based on operating and valuation metrics from publicly traded guideline companies in the regulated natural gas distribution industry. Multiples derived from the guideline companies provide an indication of how much a knowledgeable investor in the marketplace would be willing to pay for an investment in a similar company. These multiples are then applied to the appropriate operating metric to determine indications of fair value.

	If the carrying amount of a reporting unit exceeds the reporting unit’s fair value, step two must be performed to determine the amount, if any, of the goodwill impairment loss. If the carrying amount is less than fair value, further testing of goodwill impairment is not performed.

	Step two of the goodwill impairment test consists of comparing the implied fair value of the reporting unit’s goodwill against the carrying value of the goodwill. Determining the implied fair value of goodwill requires the valuation of a reporting unit’s identifiable tangible and intangible assets and liabilities as if the reporting unit had been acquired in a business combination on the testing date. The difference between the fair value of the entire reporting unit as determined in step one and the net fair value of all identifiable assets and liabilities represents the implied fair value of goodwill. A goodwill impairment charge, if any, would be the difference between the carrying amount of goodwill and the implied fair value of goodwill upon the completion of step two.

	As of October 1, 2013, the fair values of UIL Holdings’ applicable reporting units exceeded their carrying values and therefore no impairment was recognized. No events or circumstances occurred subsequent to October 1, 2013 that would make it more likely than not that the fair value of the reporting units fell below their respective carrying values.
Impairment of Long-Lived Assets and Investments	'
	Impairment of Long‑Lived Assets and Investments

	ASC 360 “Property, Plant, and Equipment” requires the recognition of impairment losses on long‑lived assets when the book value of an asset exceeds the sum of the expected future undiscounted cash flows that result from the use of the asset and its eventual disposition. If impairment arises, then the amount of any impairment is measured based on discounted cash flows or estimated fair value.

	ASC 360 also requires that rate‑regulated companies recognize an impairment loss when a regulator excludes all or part of a cost from rates, even if the regulator allows the company to earn a return on the remaining costs allowed. Under this standard, the probability of recovery and the recognition of regulatory assets under the criteria of ASC 980 must be assessed on an ongoing basis. As discussed in the description of ASC 980 in this Note (A) under “Regulatory Accounting,” determination that certain regulatory assets no longer qualify for accounting as such could have a material impact on the financial condition of UI, the Gas Companies and UIL Holdings. As a result of UI’s 2013 distribution rate proceeding, a portion of UI’s deferred storm costs and capital costs related to UI’s recently constructed administrative and operations buildings were written off. See – Note (C), Regulatory Proceedings, Electric Distribution and Transmission – Rates, for additional information.

	ASC 323 “Investments” requires that a loss in the value of an investment that is other than a temporary decline should be recognized. In accordance with ASC 323, UIL Holdings reviews its investments accounted for by the equity method for impairment by identifying and measuring losses in the value based upon a comparison of fair value to carrying value. At December 31, 2013, UIL Holdings did not have any equity investments that were impaired under this standard.
Income Taxes	'
	Income Taxes

	In accordance with ASC 740 “Income Taxes,” UIL Holdings has provided deferred taxes for all temporary book‑tax differences using the liability method. The liability method requires that deferred tax balances be adjusted to reflect enacted future tax rates that are anticipated to be in effect when the temporary differences reverse. In accordance with generally accepted accounting principles for regulated industries, UIL Holdings’ regulated subsidiaries have established a regulatory asset for the net revenue requirements to be recovered from customers for the related future tax expense associated with certain of these temporary differences. For ratemaking purposes, UIL Holdings’ regulated subsidiaries normalize all investment tax credits (ITCs) related to recoverable plant investments.

	Under ASC 740, UIL Holdings may recognize the tax benefit of an uncertain tax position only if management believes it is more likely than not that the tax position will be sustained on examination by the taxing authority based upon the technical merits of the position. The tax benefits recognized in the financial statements from such a position should be measured based upon the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. UIL Holdings’ policy is to recognize interest accrued and penalties associated with uncertain tax positions as a component of operating expense. See – Note (E), Income Taxes for additional information.

	UIL Holdings files a consolidated federal tax return which includes all of the activities of its subsidiaries. Each subsidiary company is treated as a member of the consolidated group and each subsidiary company’s current and deferred tax expense or benefit is calculated based on the separate return method.
Pension and Other Postretirement Benefits	'
	Pension and Other Postretirement Benefits

	UIL Holdings accounts for pension plan costs and other postretirement benefits, consisting principally of health and life insurance, in accordance with the provisions of ASC 715 “Compensation - Retirement Benefits.” See – Note (G), Pension and Other Benefits.
Property, Plant and Equipment	'
	Property, Plant and Equipment

	The cost of additions to property, plant and equipment and the cost of renewals and betterments are capitalized. Cost consists of labor, materials, services and certain indirect construction costs, including AFUDC. The costs of current repairs, major maintenance projects and minor replacements are charged to appropriate operating expense accounts as incurred. The original cost of utility property, plant and equipment retired or otherwise disposed of and the cost of removal, less salvage, are charged to the accumulated provision for depreciation.

	UI and the Gas Companies accrue for estimated costs of removal for certain of their plant-in-service. Such removal costs are included in the approved rates used to depreciate these assets. At the end of the service life of the applicable assets, the accumulated depreciation in excess of the historical cost of the asset provides for the estimated cost of removal. In accordance with ASC 980 “Regulated Operations,” the accrued costs of removal have been recorded as a regulatory liability.

	UIL Holdings’ property, plant and equipment as of December 31, 2013 and 2012 were comprised as follows:


			2013			2012
			(In Thousands)

	Electric distribution plant		$	979,526		$	860,096
	Electric transmission plant			630,834			577,669
	Gas distribution plant			1,444,837			1,386,288
	Software			144,494			136,219
	Building and improvements			235,002			220,821
	Land			64,848			64,421
	Other plant			192,219			184,061
	Total property, plant & equipment			3,691,760			3,429,575
	Less accumulated depreciation			944,399			893,764
				2,747,361			2,535,811
	Construction work in progress			321,319			311,340
	Net property, plant & equipment		$	3,068,680		$	2,847,151
Regulatory Accounting	'
	Regulatory Accounting

	Generally accepted accounting principles for regulated entities in the United States of America allow UIL Holdings’ regulated subsidiaries to give accounting recognition to the actions of regulatory authorities in accordance with the provisions of Accounting Standards Codification (ASC) 980 “Regulated Operations.” In accordance with ASC 980, UIL Holdings’ regulated utilities have deferred recognition of costs (a regulatory asset) or have recognized obligations (a regulatory liability) if it is probable that such costs will be recovered or obligations relieved in the future through the ratemaking process. UIL Holdings’ regulated utilities are allowed to recover all such deferred costs through its regulated rates. See Note (C), “Regulatory Proceedings,” for a discussion of the recovery of certain deferred costs, as well as a discussion of the regulatory decisions that provide for such recovery.

	UI also has obligations under long‑term power contracts, the recovery of which is subject to regulation. If UIL Holdings’ regulated utilities, or a portion of their assets or operations, were to cease meeting the criteria for application of these accounting rules, accounting standards for businesses in general would become applicable and immediate recognition of any previously deferred costs would be required in the year in which such criteria are no longer met (if such deferred costs are not recoverable in the portion of the business that continues to meet the criteria for application of ASC 980). UIL Holdings expects its regulated utilities to continue to meet the criteria for application of ASC 980 for the foreseeable future. If a change in accounting were to occur, it could have a material adverse effect on the earnings and retained earnings of the applicable regulated utility and UIL Holdings in that year and could also have a material adverse effect on the ongoing financial condition of the applicable regulated utility and UIL Holdings.

	Unless otherwise stated below, all of UIL Holdings’ regulatory assets earn a return. UIL Holdings’ regulatory assets and liabilities as of December 31, 2013 and 2012 included the following:

		Remaining		December 31,			December 31,
		Period		2013			2012
				(In Thousands)
	Regulatory Assets:
	Nuclear plant investments – above market	(a)		$	238,868		$	252,498
	Connecticut Yankee	Not applicable			-			11,129
	Unamortized redemption costs	8 to 20 years			11,301			12,103
	Pension and other post-retirement benefit plans	(b)			316,076			458,019
	Environmental remediation costs	3 years			14,953			14,772
	Hardship programs	(c)			25,019			29,852
	Debt premium	1 to 24 years			34,178			41,016
	Deferred purchased gas	(d)			2,556			12,444
	Income taxes due principally to book-tax differences	(m)			149,015			-
	Deferred income taxes	(e)			861			-
	Unfunded future income taxes	(e)			31,656			17,319
	Contracts for differences	(f)			142,743			176,597
	Excess generation service charge	(g)			6,909			8,864
	Deferred transmission expense	(h)			9,615			21,379
	Storm Costs	(i)			14,752			52,009
	Other	(j)			37,628			27,449
	Total regulatory assets				1,036,130			1,135,450
	Less current portion of regulatory assets				332,391			120,935
	Regulatory Assets, Net			$	703,739		$	1,014,515

	Regulatory Liabilities:
	Accumulated deferred investment tax credits	30 years		$	4,465		$	4,612
	Income taxes due principally to book-tax differences	(m)			200,673			41,928
	Deferred gain on sale of property	(a)			37,933			37,933
	Middletown/Norwalk local transmission network service collections	36 years			21,402			21,975
	Pension and other post-retirement benefit plans	6 years			27,686			15,016
	Deferred income taxes	(e)			43,421			41,816
	Asset retirement obligation	(k)			5,593			4,995
	Low income programs	(l)			25,300			17,651
	Asset removal costs	(j)			319,530			303,651
	Other	(j)			20,818			36,660
	Total regulatory liabilities				706,821			526,237
	Less current portion of regulatory liabilities				261,729			21,284
	Regulatory Liabilities, Net			$	445,092		$	504,953

	a) Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet as of December 31, 2013.
	(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
	(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
	(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
	(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
	(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See “-Contracts for Differences” discussion above for additional information.
	(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
	(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
	(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
	(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($11.6 million) and certain other amounts that are not currently earning a return. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the decoupling recovery period.
	(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
	(l) Various hardship and payment plan programs approved for recovery.
	(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA. In prior periods, these amounts were presented on a net basis in long-term regulatory liabilities. In the current period, due to the end of the CTA charge, the CTA regulatory liabilities have been reclassified to current regulatory liabilities and the regulatory assets not related to the CTA have been reclassified to long-term regulatory assets.
Restricted Cash	'
	Restricted Cash

	UIL Holdings’ restricted cash at December 31, 2013 and 2012 totaled $2.0 million and $2.8 million, respectively, which primarily relates to electric distribution and transmission capital projects, which have been withheld by UI and will remain in place until the verification of fulfillment of contractor obligations.
Revenues	'
	Revenues

	Regulated utility revenues are based on authorized rates applied to each customer. These retail rates are approved by regulatory bodies and can be changed only through formal proceedings.

	UI utilizes a customer accounting software package integrated with the network meter reading system to estimate unbilled revenue on a customer-by-customer basis, utilizing actual daily meter readings at the end of each month to calculate consumption and pricing for each customer. A significant portion of utility retail kilowatt-hour consumption is read through the network meter reading system. For those customers still requiring manual meter readings, consumption is estimated based upon historical usage and actual pricing for each customer.

	The Gas Companies’ unbilled revenues represent estimates of receivables for products and services provided but not yet billed. The estimates are determined based on various assumptions, such as current month energy load requirements, billing rates by customer classification and weather.
Stock-Based Compensation	'
	Stock-Based Compensation

	Certain members of management have the opportunity to earn a pre-determined number of performance shares, the number of which is predicated upon the achievement of various pre-defined performance measures over a three-year period. These performance shares are issued under the UIL Holdings 2008 Stock and Incentive Compensation Plan (2008 Stock Plan). Each award of performance shares vests at the end of a three-year cycle with the actual issuance of UIL Holdings’ common stock in respect of such performance shares following the end of each three-year cycle. A new three-year cycle begins in January of each year.

	UIL Holdings records compensation expense for these performance shares ratably over the three-year period, except in the case of retirement-eligible employees, for whom compensation expense is immediately recognized in accordance with ASC 718 “Compensation-Stock Compensation,” based on the value of the expected payout at the end of each year relative to the performance measures achieved.

	Pursuant to the 2008 Stock Plan, target amounts of 101,150 and 5,860 performance shares were granted to certain members of management in March and May of 2013, respectively; the averages of the high and low market prices on the grant dates, which approximates fair value, were $38.73 and $41.34 per share, respectively.

	Also in March 2013, UIL Holdings granted a total of 2,033 shares of restricted stock to its President and Chief Executive Officer under the 2008 Stock Plan and in accordance with his employment agreement; the average of the high and low market price on the date of grant, which approximates fair value, was $38.73 per share. Such shares vest in equal annual installments over a five-year period. In May 2013, UIL Holdings granted a total of 2,177 shares of restricted stock to an executive under the Amended and Restated UIL Holdings 2008 Stock and Incentive Compensation Plan; the average of the high and low market price on the date of grant, which approximates fair value, was $41.34 per share. Such shares vest in May 2016.

	Also in May 2013, UIL Holdings granted a total of 21,558 shares of restricted stock to non-employee directors under the 2008 Stock Plan; the average of the high and low market price on the date of grant, which approximates fair value, was $40.69 per share. Such shares vest in May 2014.

	As of December 31, 2013, the total number of shares authorized for stock-based compensation plans was 4,150,000. Total stock-based compensation expense for the years ended December 31, 2013, 2012 and 2011 was $5.3 million, $4.9 million and $5.3 million, respectively.
Variable Interest Entities	'
	Variable Interest Entities

	UIL Holdings has identified GenConn as a variable interest entity (VIE), which is accounted for under the equity method. UIL Holdings is not the primary beneficiary of GenConn, as defined in ASC 810 “Consolidation,” because it shares control of all significant activities of GenConn with its joint venturer, NRG affiliates. As such, GenConn is not subject to consolidation. GenConn recovers its costs through CfDs, which are cost of service-based and have been approved by PURA. As a result, with the achievement of commercial operation by GenConn Devon and GenConn Middletown, UIL Holdings’ exposure to loss is primarily related to the potential for unrecovered GenConn operating or capital costs in a regulatory proceeding, the effect of which would be reflected in the carrying value of UIL Holdings’ 50% ownership position in GenConn and through “Income from Equity Investments” in UIL Holdings’ Consolidated Financial Statements. Such exposure to loss cannot be determined at this time. For further discussion of GenConn, see “–Equity Investments” as well as Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Equity Investment in Peaking Generation.”

	UIL Holdings has identified the selected capacity resources with which UI has CfDs as VIEs and has concluded that UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these capacity resources. As such, UIL Holdings has not consolidated the selected capacity resources. UI’s maximum exposure to loss through these agreements is limited to the settlement amount under the CfDs as described in “–Derivatives – Contracts for Differences (CfDs)” above. UI has no requirement to absorb additional losses nor has UI provided any financial or other support during the periods presented that were not previously contractually required.

	UIL Holdings has identified the entities for which UI is required to enter into long-term contracts to purchase Renewable Energy Credits (RECs) as VIEs. In assessing these contracts for VIE identification and reporting purposes, UIL Holdings has aggregated the contracts based on similar risk characteristics and significance to UI. UI is not the primary beneficiary as UI does not have the power to direct any of the significant activities of these entities. UI’s exposure to loss is primarily related to the purchase and resale of the RECs, but, any losses incurred are recoverable through electric rates. For further discussion of RECs, see Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – New Renewable Source Generation.”
New Accounting Standards	'
	New Accounting Standards

	In February 2013, the FASB issued updated guidance to ASC 220 “Comprehensive Income” which requires disclosure of amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present either on the face of the Consolidated Statements of Income or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required to be reclassified to net income in its entirety in the same reporting period. For amounts not reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide additional detail about those amounts. The guidance was effective prospectively for the first quarter of 2013. The adoption of this update did not have a material impact on UIL Holdings’ consolidated financial statements.

	In July 2013, the FASB issued updated guidance to ASC 740 “Income Taxes” which prescribes the presentation of an unrecognized tax benefit when a net operating loss carry forward, a similar tax loss, or a tax credit carry forward exists. This guidance is effective during interim and annual periods beginning after December 15, 2013 and is to be applied on a prospective basis. The implementation of this guidance is not expected to have a material impact on UIL Holdings’ consolidated financial statements.

STATEMENT_OF_ACCOUNTING_POLICI2

STATEMENT OF ACCOUNTING POLICIES (Tables)	12 Months Ended
STATEMENT OF ACCOUNTING POLICIES (Tables)	Dec. 31, 2013
STATEMENT OF ACCOUNTING POLICIES [Abstract]	'
ARO Activity for 2013 and 2012	'
	ARO activity for 2013 and 2012 is as follows:

			2013			2012
			(In Thousands)
	Balance as of December 31		$	18,289		$	18,058
	Liabilities incurred during the year			-			-
	Liabilities settled during the year			(740	)		(718	)
	Accretion			961			949
	Balance as of December 31		$	18,510		$	18,289
Value of Gross Derivative Assets and Liabilities	'
	UIL Holdings’ regulated subsidiaries are parties to contracts, and involved in transactions, that are derivatives. The values of the gross derivative assets and liabilities as of December 31, 2013 and 2012 were as follows:

			December 31,			December 31,
			2013			2012
			(In Thousands)
	Gross derivative assets:
	Current Assets		$	9,098		$	12,671
	Deferred Charges and Other Assets		$	44,349		$	67,167

	Gross derivative liabilties:
	Current Liabilities		$	26,976		$	30,804
	Noncurrent Liabilities		$	169,327		$	224,639
Unrealized Gains and Losses From Mark-To-Market Adjustments	'
	The unrealized gains and losses from fair value adjustments to these derivatives recorded in regulatory assets or regulatory liabilities for years ended December 31, 2013 and 2012 were as follows:

			Year Ended
			December 31,
			2013			2012
			(In Thousands)

	Regulatory Assets - Derivative liabilities		$	(33,819	)	$	(7,500	)

	Regulatory Liabilities - Derivative assets		$	-		$	12
Reconciliation of Basic and Diluted Earnings Per Share	'
	The following table presents a reconciliation of the basic and diluted earnings per share calculations for the years 2013, 2012 and 2011:


			Year Ended December 31,
			2013			2012			2011
			(In Thousands, except per share amounts)

	Numerator:
	Net income attributable to UIL Holdings		$	115,265		$	103,637		$	99,656
	Less: Net income allocated to unvested units			117			184			210
	Net income attributable to common shareholders		$	115,148		$	103,453		$	99,446

	Denominator:
	Basic average number of shares outstanding			52,415			50,831			50,609
	Effect of dilutive securities			296			277			317
	Diluted average number of shares outstanding			52,711			51,108			50,926

	Earnings per share:
	Basic		$	2.2		$	2.04		$	1.96
	Diluted		$	2.18		$	2.02		$	1.95
Net Property, Plant and Equipment	'
	UIL Holdings’ property, plant and equipment as of December 31, 2013 and 2012 were comprised as follows:


			2013			2012
			(In Thousands)

	Electric distribution plant		$	979,526		$	860,096
	Electric transmission plant			630,834			577,669
	Gas distribution plant			1,444,837			1,386,288
	Software			144,494			136,219
	Building and improvements			235,002			220,821
	Land			64,848			64,421
	Other plant			192,219			184,061
	Total property, plant & equipment			3,691,760			3,429,575
	Less accumulated depreciation			944,399			893,764
				2,747,361			2,535,811
	Construction work in progress			321,319			311,340
	Net property, plant & equipment		$	3,068,680		$	2,847,151
Regulatory Assets and Liabilities	'
	Unless otherwise stated below, all of UIL Holdings’ regulatory assets earn a return. UIL Holdings’ regulatory assets and liabilities as of December 31, 2013 and 2012 included the following:

		Remaining		December 31,			December 31,
		Period		2013			2012
				(In Thousands)
	Regulatory Assets:
	Nuclear plant investments – above market	(a)		$	238,868		$	252,498
	Connecticut Yankee	Not applicable			-			11,129
	Unamortized redemption costs	8 to 20 years			11,301			12,103
	Pension and other post-retirement benefit plans	(b)			316,076			458,019
	Environmental remediation costs	3 years			14,953			14,772
	Hardship programs	(c)			25,019			29,852
	Debt premium	1 to 24 years			34,178			41,016
	Deferred purchased gas	(d)			2,556			12,444
	Income taxes due principally to book-tax differences	(m)			149,015			-
	Deferred income taxes	(e)			861			-
	Unfunded future income taxes	(e)			31,656			17,319
	Contracts for differences	(f)			142,743			176,597
	Excess generation service charge	(g)			6,909			8,864
	Deferred transmission expense	(h)			9,615			21,379
	Storm Costs	(i)			14,752			52,009
	Other	(j)			37,628			27,449
	Total regulatory assets				1,036,130			1,135,450
	Less current portion of regulatory assets				332,391			120,935
	Regulatory Assets, Net			$	703,739		$	1,014,515

	Regulatory Liabilities:
	Accumulated deferred investment tax credits	30 years		$	4,465		$	4,612
	Income taxes due principally to book-tax differences	(m)			200,673			41,928
	Deferred gain on sale of property	(a)			37,933			37,933
	Middletown/Norwalk local transmission network service collections	36 years			21,402			21,975
	Pension and other post-retirement benefit plans	6 years			27,686			15,016
	Deferred income taxes	(e)			43,421			41,816
	Asset retirement obligation	(k)			5,593			4,995
	Low income programs	(l)			25,300			17,651
	Asset removal costs	(j)			319,530			303,651
	Other	(j)			20,818			36,660
	Total regulatory liabilities				706,821			526,237
	Less current portion of regulatory liabilities				261,729			21,284
	Regulatory Liabilities, Net			$	445,092		$	504,953

	a) Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UI’s 2013 distribution rate request, PURA approved UI’s proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet as of December 31, 2013.
	(b) Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) “Pension and Other Benefits” for additional information.
	(c) Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
	(d) Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
	(e) The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
	(f) Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See “-Contracts for Differences” discussion above for additional information.
	(g) Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
	(h) Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
	(i) Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the recovery of these costs.
	(j) Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($11.6 million) and certain other amounts that are not currently earning a return. See Note (C) “Regulatory Proceedings – Electric Distribution and Transmission – Rates” for a discussion of the decoupling recovery period.
	(k) The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
	(l) Various hardship and payment plan programs approved for recovery.
	(m) Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA. In prior periods, these amounts were presented on a net basis in long-term regulatory liabilities. In the current period, due to the end of the CTA charge, the CTA regulatory liabilities have been reclassified to current regulatory liabilities and the regulatory assets not related to the CTA have been reclassified to long-term regulatory assets.

CAPITALIZATION_Tables

CAPITALIZATION (Tables)	12 Months Ended
CAPITALIZATION (Tables)	Dec. 31, 2013
CAPITALIZATION [Abstract]	'
Restricted stock activity	'
	Restricted stock activity for 2013 is as follows:

		Number			Weighted Average
		of Shares			Grant Date
					Fair Value
	Nonvested Balance – December 31, 2012		74,131		$	30.49
	Granted		25,768		$	40.59
	Forfeited		(1,672	)	$	29.91
	Vested		(67,307	)	$	30.5
	Nonvested Balance – December 31, 2013		30,920		$	38.9
Performance share activity	'
	Performance share activity for 2013 is as follows:

		Number			Weighted Average
		of Performance			Grant Date
		Shares			Fair Value
	Nonvested Balance – December 31, 2012		325,888		$	31.39
	Granted		107,010		$	38.87
	Forfeited		(36,740	)		N/A
	Vested		(61,150	)	$	28.53
	Nonvested Balance – December 31, 2013		335,008		$	34.62
Stock option transactions	'
	Stock option transactions for 2013, 2012 and 2011 are as follows:

		Number			Option Price		Average
		of Options			per Share		Exercise
							Price
	Balance – December 31, 2010		134,994			$21.68-$34.51		$31.70
	Granted		-			N/A		N/A
	Forfeited		(7,910	)		N/A		N/A
	Exercised		(28,864	)		$21.68-$31.25		N/A
	Balance – December 31, 2011		98,220			$21.68-$33.96		$33.39
	Granted		-			N/A		N/A
	Forfeited		(38,000	)		N/A		N/A
	Exercised		(56,887	)		$31.25-$33.96		N/A
	Balance – December 31, 2012		3,333			$21.68		$21.68
	Granted		-			N/A		N/A
	Forfeited		-			N/A		N/A
	Exercised		(3,333	)		21.68		N/A
	Balance – December 31, 2013		-			N/A		N/A

	Exercisable at December 31, 2011		98,220			$21.68-$33.96		$33.39
	Exercisable at December 31, 2012		3,333			$21.68		$21.68
	Exercisable at December 31, 2013		-			N/A		N/A
Long-term debt	'

	Long-Term Debt
		December 31,
		2013			2012
		(In Thousands)
	UIL Holdings
	4.625% Unsecured Senior Notes, due 2020	$	450,000		$	450,000

	UI
	Pollution Control Revenue Bonds:

	4.50% 2010 Series, due 2027		27,500			27,500
	Auction Rate, 2003 Series, due 2033 (1)		64,460			64,460

	Senior Unsecured Notes:

	6.06% Senior Notes, Series A and B, due 2017		70,000			70,000
	2.98% Senior Notes, Series A due 2019		31,000			31,000
	3.61% Senior Notes, Series B and C and 6.26% Senior Notes, Series C and D, due 2022		162,500			162,500
	6.51% Senior Notes, Series E and F due 2037		28,000			28,000
	6.46% Senior Notes, Series A and 6.51%, Senior Notes, Series B, due 2018		100,000			100,000
	6.61% Senior Notes, Series C, due 2020		50,000			50,000
	5.61% Senior Notes, due 2025		50,000			50,000
	6.09% Senior Notes, due 2040		100,000			100,000
	4.89% Senior Notes, Series D and E, due 2042		87,000			87,000
	3.95% Senior Notes, Series F, due 2023		75,000			-

	Gas Companies
	Senior Secured Notes:

	3.88% - 7.50% Senior Secured Medium Term Note IV, due 2018 - 2041		100,000			100,000
	5.77% - 6.38% Senior Secured Medium Term Notes III, due 2025 - 2037		85,000			85,000
	6.88% - 7.95% Senior Secured Medium Term Notes I, due 2026 - 2028		29,000			29,000
	10.06% First Mortgage Bond Series P, due 2019		10,000			10,000

	Unsecured Notes:

	4.76% - 9.60% Senior Unsecured Notes, due 2020 - 2021		19,635			21,090
	6.85% - 9.10% Unsecured Medium Term Notes, Series A, due 2013 - 2017		30,000			50,000
	6.50% Unsecured Medium Term Note, Series D, due 2013		-			20,000
	8.12% - 8.49% Unsecured Medium Term Notes, Series B, due 2014 - 2024		10,000			10,000
	5.63% - 6.66% Unsecured Medium Term Notes, Series C, due 2035 - 2037		65,000			65,000
	4.30% - 5.23% Medium Term Note, Series D, due 2028 - 2043		45,000			-
	5.33% Senior Notes, Series A, due 2043		15,000			-

	Long-Term Debt		1,704,095			1,610,550
	Less: Current portion of long-term debt (2)		11,834			48,296
	Less: Unamortized discount		2,597			2,916
	Plus: Unamortized premium		34,178			41,016
	Net Long-Term Debt	$	1,723,842		$	1,600,354

	(1) On December 31, 2013, the interest rate on the Bonds was 0.34%. The interest rate on these Bonds is reset through an auction held every 35 days.
	(2) Includes the current portion of unamortized premium.
Maturities and mandatory redemptions and repayments	'
	Information regarding maturities and mandatory redemptions/repayments are set forth below:

		2014			2015		2016		2017		2018 &
		2014			2015		2016		2017		thereafter
	(In Thousands)
	Maturities	$	6,455		$	1,455	$	11,455	$	91,455	$	1,593,275

REGULATORY_PROCEEDINGS_Tables

REGULATORY PROCEEDINGS (Tables)	12 Months Ended
REGULATORY PROCEEDINGS (Tables)	Dec. 31, 2013
REGULATORY PROCEEDINGS [Abstract]	'
Long-term Supply Commitment	'
	The Gas Companies acquire firm transportation capacity on interstate pipelines under long-term contracts and utilize that capacity to transport both natural gas supply purchased and natural gas withdrawn from storage to the local distribution system. Collectively, the Gas Companies hold approximately 100 firm transportation contracts on 12 different pipelines. Three of those pipelines, Tennessee Gas Pipeline, Algonquin Gas Transmission and Iroquois Gas Transmission, interconnect with one or more of the Gas Companies’ distribution system and the other pipelines provide indirect services upstream of the city gates. The prices and terms and conditions of the long-term contracts for firm transportation capacity are regulated by the FERC. The actual reasonable costs of such contracts are passed through to customers through state regulated purchased gas adjustment mechanisms. The future obligations under these contracts as of December 31, 2013 are as follows:

		(In Thousands)
	2014		126,485
	2015		112,665
	2016		99,467
	2017		72,369
	2018		42,609
	2019-after		72,979
		$	526,574

SHORTTERM_CREDIT_ARRANGEMENTS_

SHORT-TERM CREDIT ARRANGEMENTS (Tables)	12 Months Ended
SHORT-TERM CREDIT ARRANGEMENTS (Tables)	Dec. 31, 2013
SHORT TERM CREDIT ARRANGEMENTS [Abstract]	'
Short-term borrowings	'
	Information with respect to short-term borrowings is set forth below:

		2013			2012
		($ In Thousands)
	UIL Holdings

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	202,000		$	168,000
	Average aggregate short-term borrowings outstanding during the year*	$	152,455		$	109,268
	Weighted average interest rate*		1.43	%		1.61	%
	Principal amounts outstanding at year-end	$	-		$	157,000

	UI

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	60,000		$	243,000
	Average aggregate short-term borrowings outstanding during the year*	$	13,510		$	78,533
	Weighted average interest rate*		1.4	%		1.58	%
	Principal amounts outstanding at year-end	$	-		$	30,000

	Gas Companies

	Maximum aggregate principal amount of short-term borrowing outstanding at any month-end	$	-		$	6,000
	Average aggregate short-term borrowings outstanding during the year*	$	-		$	128
	Weighted average interest rate*		0	%		1.59	%
	Principal amounts outstanding at year-end	$	-		$	-

	* Average short‑term borrowings represent the sum of daily borrowings outstanding, weighted for the number of days outstanding and divided by the number of days in the period. The weighted average interest rate is determined by dividing interest expense by the amount of average borrowings.

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
INCOME TAXES (Tables)	Dec. 31, 2013
INCOME TAXES [Abstract]	'
Components of income tax	'

		2013			2012			2011
		(In Thousands)
	Income tax expense consists of:
	Income tax provisions:
	Current
	Federal	$	(443	)	$	5,830		$	(16,626	)
	State		(1,149	)		1,110			(3,951	)
	Total current		(1,592	)		6,940			(20,577	)
	Deferred
	Federal		64,931			61,510			72,840
	State		6,164			6,611			10,433
	Total deferred		71,095			68,121			83,273

	Investment tax credits		(195	)		(195	)		(195	)

	Total income tax expense	$	69,308		$	74,866		$	62,501
Reconciliation of statutory federal tax rate to effective tax rate	'
	Total income taxes differ from the amounts computed by applying the federal statutory tax rate to income before taxes. The reasons for the differences are as follows:

		2013			2012			2011
		(In Thousands)

	Book income before income taxes	$	184,625		$	178,567		$	162,211

	Computed tax at federal statutory rate	$	64,619		$	62,499		$	56,774
	Increases (reductions) resulting from:
	Investment tax credits		(195	)		(195	)		(195	)
	Allowance for equity funds used during construction		(3,784	)		(2,749	)		(3,689	)
	Amortization of nuclear plant regulatory assets		6,867			9,334			8,885
	State income taxes, net of federal income tax benefits		3,259			5,018			4,214
	Other items, net		(1,458	)		959			(3,488	)

	Total income tax expense	$	69,308		$	74,866		$	62,501

	Effective income tax rates		37.5	%		41.9	%		38.5	%
Changes in gross income tax reserves	'
	The following table sets forth a reconciliation of the changes in the gross income tax reserves for the years ended December 31, 2013 and 2012:

		2013			2012
		(In Thousands)
	Balance as of December 31	$	-		$	13,676
	Increases for tax positions related to current year		-			-
	Reductions for tax positions of prior years		-			(13,676	)
	Balance as of December 31	$	-		$	-
Deferred income taxes by balance sheet classification	'
	ASC 740 requires that all current deferred tax assets and liabilities within each particular tax jurisdiction be offset and presented as a single amount in the Consolidated Balance Sheet. A similar procedure is followed for all non-current deferred tax assets and liabilities. Amounts in different tax jurisdictions cannot be offset against each other. The amount of deferred income taxes as of December 31, 2013 and 2012 included on the following lines of the Consolidated Balance Sheet is as follows:

		2013			2012
		(In Thousands)
	Assets:
	Deferred income taxes	$	21,742		$	41,605
	Liabilities:
	Deferred income taxes		540,542			462,940
	Deferred income taxes – net	$	518,800		$	421,335
Deferred tax assets and liabilities	'
	The following table summarizes UIL Holdings’ deferred income tax assets and liabilities as of December 31, 2013 and 2012.

		2013			2012
		(In Thousands)
	Deferred income tax assets:
	Post-retirement benefits	$	90,300		$	151,203
	Accrued removal obligation		119,904			105,329
	Net operating loss carry forward		42,818			26,775
	Other		104,467			58,266
		$	357,489		$	341,573

	Deferred income tax liabilities:
	Accelerated depreciation timing differences	$	364,321		$	317,885
	Plant basis differences		243,629			178,989
	Storm regulatory asset		5,883			21,102
	Regulatory deferrals related to pension and other post-retirement benefits		110,980			171,576
	Investment in GenConn		53,350			52,920
	Other		98,126			20,436
		$	876,289		$	762,908
Schedule of carry forward balances	'
	The following table sets forth the carry forward balances for the years ended December 31, 2013 and 2012:

		2013			2012			Year
								Expiration
								Begins
		(In Thousands)
	Federal net operating loss	$	122,339		$	76,500			2032
	Alternative minimum tax credit		2,697			2,488			N/A
	State tax credits		7,289			3,104			2016

SUPPLEMENTARY_INFORMATION_Tabl

SUPPLEMENTARY INFORMATION (Tables)	12 Months Ended
SUPPLEMENTARY INFORMATION (Tables)	Dec. 31, 2013
SUPPLEMENTARY INFORMATION [Abstract]	'
Supplementary Information	'

		2013			2012		2011
		(In Thousands)
	Depreciation and Amortization
	Property, plant, and equipment depreciation	$	120,301		$	112,002	$	98,343
	Amortization of nuclear plant regulatory assets		47,476			46,550		44,635
	Amortization of other regulatory assets		22,050			22,745		24,436
	Other		29			51		48
	Total Amortization		69,555			69,346		69,119
	Total Depreciation and Amortization	$	189,856		$	181,348	$	167,462

	Taxes - Other than Income Taxes
	Operating:
	Connecticut gross earnings	$	75,330		$	65,753	$	69,906
	Local real estate and personal property		46,567			40,588		34,902
	Payroll taxes		8,005			7,274		9,373
	Other		556			422		30
	Total Taxes - Other than Income Taxes	$	130,458		$	114,037	$	114,211

	Other Income and (Deductions), net
	Interest income	$	2,733		$	2,631	$	3,483
	Allowance for funds used during construction - equity		10,811			7,480		10,539
	Allowance for funds used during construction - debt		7,170			6,979		9,143
	Weather insurance		(70	)		3,488		3,090
	TSO incentives		-			2,745		-
	Other		(11	)		1,923		677
	Total Other Income and (Deductions), net	$	20,633		$	25,246	$	26,932

PENSION_AND_OTHER_BENEFITS_Tab

PENSION AND OTHER BENEFITS (Tables)	12 Months Ended
PENSION AND OTHER BENEFITS (Tables)	Dec. 31, 2013
PENSION AND OTHER BENEFITS [Abstract]	'
Changes in Benefit Obligation	'
	The following table represents the change in benefit obligation, change in plan assets and the respective funded status of UIL Holdings’ pension and other postretirement plans as of December 31, 2013 and 2012. Plan assets and obligations have been measured as of December 31, 2013 and 2012.

								Other Post-Retirement
		Pension Benefits						Benefits
		2013			2012			2013			2012
	Change in Benefit Obligation:	(In Thousands)
	Benefit obligation at beginning of year	$	950,608		$	792,101		$	136,687		$	122,382
	Service cost		14,783			12,032			1,923			1,604
	Interest cost		39,948			41,470			5,539			6,246
	Participant contributions		-			-			1,253			1,305
	Settlements (1)		(2,367	)		-			-			-
	Actuarial (gain) loss		(96,739	)		149,088			(13,893	)		12,500
	Benefits paid (including expenses)		(46,971	)		(44,083	)		(11,807	)		(7,350	)
	Benefit obligation at end of year	$	859,262		$	950,608		$	119,702		$	136,687

	Change in Plan Assets:
	Fair value of plan assets at beginning of year	$	625,061		$	548,122		$	38,540		$	37,573
	Actual return on plan assets		54,259			71,595			6,003			4,092
	Employer contributions		58,428			49,427			-			-
	Participant contributions		-			-			1,253			1,305
	Settlements (1)		(2,367	)		-			-			-
	Benefits paid (including expenses)		(46,971	)		(44,083	)		(4,633	)		(4,430	)
	Fair value of plan assets at end of year	$	688,410		$	625,061		$	41,163		$	38,540

	Funded Status at December 31:
	Projected benefits (less than) greater than plan assets	$	170,852		$	325,547		$	78,539		$	98,147

	Amounts Recognized in the Statement of Financial Position consist of:
	Non-current assets	$	-		$	-		$	-		$	-
	Current liabilities	$	-		$	-		$	-		$	-
	Non-current liabilities	$	170,852		$	325,547		$	78,539		$	98,147

	Amounts Recognized as a Regulatory Asset consist of:
	Transition obligation (asset)	$	-		$	-		$	-		$	-
	Prior service cost		365			859			1,447			45
	Net (gain) loss		123,178			244,032			(792	)		19,643
	Total recognized as a regulatory asset	$	123,543		$	244,891		$	655		$	19,688

	(1) Reflects settlement charges resulting from a distribution to a former employee upon retirement
Information on Pension Plans with an Accumulated Benefit Obligations in excess of Plan Assets	'
	Information on Pension Plans with an Accumulated Benefit Obligation in excess of Plan Assets:
	Projected benefit obligation	$	859,262		$	950,608			N/A			N/A
	Accumulated benefit obligation	$	784,081		$	858,803			N/A			N/A
	Fair value of plan assets	$	688,410		$	625,061			N/A			N/A
Weighted average actuarial assumptions used in calculating benefit obligations.	'
	The following weighted average actuarial assumptions were used in calculating the benefit obligations at December 31:
	Discount rate (Qualified Plans)		5.2	%		4.25	%		N/A			N/A
	Discount rate (Non-Qualified Plans)		4.9	%		4	%		N/A			N/A
	Discount rate (Other Post-Retirement Benefits)		N/A			N/A			4.85-5.20	%		4.00-4.25	%
	Average wage increase		3.50-3.80	%		3.50-3.80	%		N/A			N/A
	Health care trend rate (current year)		N/A			N/A			7	%		7.5	%
	Health care trend rate (2019-2028 forward)		N/A			N/A			5	%		5	%
	N/A – not applicable
Components of net Periodic Benefit Cost for Pension and Other Postretirement Benefits (OPEB)	'

		For the Year Ended December 31,
		Pension Benefits									Other Post-Retirement Benefits
		2013			2012			2011			2013			2012			2011
		(In Thousands)
	Components of net periodic benefit cost:
	Service cost	$	14,783		$	12,032		$	12,574		$	1,923		$	1,604		$	2,164
	Interest cost		39,948			41,470			40,484			5,539			6,246			6,634
	Expected return on plan assets		(51,453	)		(44,874	)		(42,588	)		(2,590	)		(2,503	)		(2,965	)
	Amortization of:
	Prior service costs		605			647			643			(50	)		(69	)		(101	)
	Transition obligation (asset)		-			-			-			-			392			1,020
	Actuarial (gain) loss		20,829			13,173			14,032			1,776			965			2,008
	Settlements (1)		632			-			-			-			-			-
	Net periodic benefit cost	$	25,344		$	22,448		$	25,145		$	6,598		$	6,635		$	8,760

	Other Changes in Plan Assets and Benefit Obligations Recognized as a Regulatory Asset:
	Net (gain) loss	$	(99,572	)	$	122,368		$	34,524		$	(17,257	)	$	10,760		$	(6,608	)
	Amortization of:
	Current year prior service costs		111			-			-			1,352			-			-
	Prior service costs		(605	)		(647	)		(626	)		50			69			101
	Transition obligation (asset)		-			-			-			-			(392	)		(1,020	)
	Settlements (1)		(632	)		-			-						-			-
	Actuarial (gain) loss		(20,829	)		(13,173	)		(14,032	)		(1,776	)		(965	)		(2,008	)
	Total recognized as regulatory asset	$	(121,527	)	$	108,548		$	19,866		$	(17,631	)	$	9,472		$	(9,535	)

	Total recognized in net periodic benefit costs and regulatory asset	$	(96,183	)	$	130,996		$	45,011		$	(11,033	)	$	16,107		$	(775	)

	Estimated Amortizations from Regulatory Assets into Net Periodic Benefit Cost for the next 12 month period:
	Amortization of transition obligation	$	-		$	-		$	-		$	-		$	-		$	392
	Amortization of prior service cost		291			605			647			284			(50	)		(69	)
	Amortization of net (gain) loss		12,386			20,808			13,173			(298	)		1,939			965
	Total estimated amortizations	$	12,677		$	21,413		$	13,820		$	(14	)	$	1,889		$	1,288

	(1) Reflects settlement charges resulting from a distribution to a former employee upon retirement
Weighted average actuarial assumption used in calculating net periodic benefit cost	'
	The following actuarial weighted average assumptions were used in calculating net periodic benefit cost:
	Discount rate		4.00-4.25	%		5.05-5.30	%		5.10-5.35	%		4.00-4.25	%		5.05-5.30	%		5.15-5.30	%
	Average wage increase		3.50-3.80	%		3.50-3.80	%		3.50-3.80	%		N/A			N/A			N/A
	Return on plan assets		7.75-8.00	%		7.75-8.00	%		8.25-8.50	%		5.56-8.00	%		5.56-8.00	%		5.86-8.25	%
	Health care trend rate (current year)		N/A			N/A			N/A			7.5	%		8	%		7.80-8.50	%
	Health care trend rate (2019 forward)		N/A			N/A			N/A			5	%		5	%		4.50-5.00	%
	N/A – not applicable
Effect of one percentage change in assumed health care cost trend rate	'
	A one percentage point change in the assumed health care cost trend rate would have the following effects:

		1% Increase			1% Decrease
		(In Thousands)
	Aggregate service and interest cost components	$	751		$	(610	)
	Accumulated post-retirement benefit obligation	$	9,559		$	(7,942	)
Expected future benefit payments	'
	The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid:

	Year	Pension Benefits			Other
					Postretirement
					Benefits
		(In Thousands)
	2014	$	45,266		$	7,447
	2015	$	49,699		$	7,710
	2016	$	49,437		$	7,763
	2017	$	51,358		$	7,892
	2018	$	54,013		$	7,969
	2019-2022	$	288,030		$	40,009

LEASE_OBLIGATIONS_Tables

LEASE OBLIGATIONS (Tables)	12 Months Ended
LEASE OBLIGATIONS (Tables)	Dec. 31, 2013
LEASE OBLIGATIONS [Abstract]	'
Future minimum payments	'
	Operating leases, which are charged to operating expense, consist principally of leases of office space and facilities, land, railroad rights of way and a wide variety of equipment. The future minimum lease payments under these operating leases are estimated to be as follows:

		(In Thousands)
	2014	$	4,504
	2015		3,576
	2016		3,606
	2017		3,691
	2018		3,537
	2019-after		39,820
		$	58,734
Schedule of rental payments charged to operating expenses	'
	Rental payments charged to operating expenses in 2013, 2012 and 2011 were as follows:

		Year Ended December 31,
		2013		2012		2011
		(In Thousands)

	Rental payments	$	5,886	$	11,639	$	17,676
	Less: Sublease rental payments received		-		241		1,148
	Rental payments charged to operating expenses	$	5,886	$	11,398	$	16,528

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
FAIR VALUE MEASUREMENTS (Tables)	Dec. 31, 2013
FAIR VALUE MEASUREMENTS [Abstract]	'
Fair Value of Financial Assets and Liabilities	'
	The following tables set forth the fair value of UIL Holdings’ financial assets and liabilities, other than pension benefits and other postretirement benefits as of December 31, 2013 and December 31, 2012.

			Fair Value Measurements Using
			Quoted Prices in				Significant			Significant			Total
			Active Markets				Other			Unobservable
			for Identical				Observable			Inputs (Level 3)
			Assets (Level 1)				Inputs (Level 2)
	31-Dec-13		(In Thousands)
	Assets:
	Derivative assets		$	-			$	-		$	53,447		$	53,447
	Noncurrent investments available for sale			11,148				-			-			11,148
	Deferred Compensation Plan			3,775				-			-			3,775
	Supplemental retirement benefit trust life insurance policies			-				7,898			-			7,898
			$	14,923			$	7,898		$	53,447		$	76,268

	Liabilities:
	Derivative liabilities		$	-			$	-		$	196,233		$	196,233
	Long-term debt			-				1,846,867			-			1,846,867
			$	-			$	1,846,867		$	196,233		$	2,043,100

	Net fair value assets/(liabilities), December 31, 2013		$	14,923			$	(1,838,969	)	$	(142,786	)	$	(1,966,832	)

			Fair Value Measurements Using
			Quoted Prices in				Significant			Significant			Total
			Active Markets				Other			Unobservable
			for Identical				Observable			Inputs (Level 3)
			Assets (Level 1)				Inputs (Level 2)
	31-Dec-12
	Assets:
	Derivative assets		$	-			$	-		$	78,838		$	78,838
	Noncurrent investments available for sale			9,902				-			-			9,902
	Deferred Compensation Plan			3,745				-			-			3,745
	Supplemental retirement benefit trust life insurance policies			-				6,438			-			6,438
			$	13,647			$	6,438		$	78,838		$	98,923

	Liabilities:
	Derivative liabilities		$	-			$	-		$	255,443		$	255,443
	Long-term debt			-				1,886,440			-			1,886,440
			$	-			$	1,886,440		$	255,443		$	2,141,883

	Net fair value assets/(liabilities), December 31, 2011		$	13,647			$	(1,880,002	)	$	(176,605	)	$	(2,042,960	)
Additional quantitative information about Level 3 fair value measurements	'
	Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The derivative assets consist primarily of CfDs. The determination of fair value of the CfDs was based on a probability-based expected cash flow analysis that was discounted at the December 31, 2013 or December 31, 2012 risk-free interest rates, as applicable, and an adjustment for non-performance risk using credit default swap rates. Certain management assumptions were required, including development of pricing that extended over the term of the contracts. UIL Holdings believes this methodology provides the most reasonable estimates of the amount of future discounted cash flows associated with the CfDs. Additionally, on a quarterly basis, analytics are performed to ensure that the fair value of the derivatives is consistent with changes, if any, in the various fair value model inputs. Additional quantitative information about Level 3 fair value measurements is as follows:

		Unobservable Input		Range

	Contracts for differences	Risk of non-performance			0.00% - 0.62	%
		Discount rate			1.75% - 3.21	%
		Forward pricing ($ per MW)			$1.40 - $9.83
Changes in Fair Value of Assets and Liabilities Classified as level 3	'
	The following tables set forth a reconciliation of changes in the fair value of the assets and liabilities above that are classified as Level 3 in the fair value hierarchy for the twelve month periods ended December 31, 2013 and 2012.

			Year Ended
			31-Dec-13
			(In Thousands)

	Net derivative assets/(liabilities), December 31, 2012		$	(176,605	)
	Unrealized gains and (losses), net
	Included in earnings			-
	Included in regulatory assets/(liabilities)			33,819
	Settlements			-
	Net derivative assets/(liabilities), December 31, 2013		$	(142,786	)

	Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of December 31, 2013		$	33,819

			Year Ended
			31-Dec-12
			(In Thousands)

	Net derivative assets/(liabilities), December 31, 2011		$	(180,581	)
	Unrealized gains and (losses), net
	Included in earnings			3,488
	Included in regulatory assets/(liabilities)			7,488
	Settlements			(7,000	)
	Net derivative assets/(liabilities), December 31, 2012		$	(176,605	)

	Change in unrealized gains (losses), net relating to net derivative assets/(liabilities), still held as of December 31, 2012		$	7,488
Change in Regulatory Asset/(Liability) Balance	'
	The following table sets forth a reconciliation of changes in the net regulatory asset/(liability) balances that were established to recover any unrealized gains/(losses) associated with the CfDs for the years ended December 31, 2013 and 2012. The amounts offset the net CfDs liabilities included in the derivative liabilities detailed above.

			Year Ended
			31-Dec-13
			(In Thousands)

	Net regulatory assets/(liabilities), December 31, 2012		$	176,605
	Unrealized (gains) and losses, net			(33,819	)
	Net regulatory assets/(liabilities), December 31, 2013		$	142,786

			Year Ended
			31-Dec-12
			(In Thousands)

	Net regulatory assets/(liabilities), December 31, 2011		$	184,093
	Unrealized (gains) and losses, net			(7,488	)
	Net regulatory assets/(liabilities), December 31, 2012		$	176,605
Fair value of pension and OPEB assets	'
	The following tables set forth the fair values of UIL Holdings’ pension and OPEB assets as of December 31, 2013 and 2012.

			Fair Value Measurements Using
			Quoted Prices in				Significant			Significant			Total
			Active Markets for				Other			Unobservable
			Identical Assets				Observable			Inputs (Level 3)
			(Level 1)				Inputs (Level 2)
			(In Thousands)
	31-Dec-13

	Pension assets
	Cash and cash equivalents		$	-			$	-		$	-		$	-
	Mutual funds			-				653,579			-			653,579
	Hedge fund			-				-			34,831			34,831
				-				653,579			34,831			688,410
	OPEB assets
	Mutual funds			41,163				-			-			41,163
				41,163				-			-			41,163

	Fair value of plan assets, December 31, 2013		$	41,163			$	653,579		$	34,831		$	729,573

	31-Dec-12

	Pension assets
	Cash and cash equivalents		$	1,606			$	-		$	-		$	1,606
	Mutual funds			-				595,772			-			595,772
	Hedge fund			-				-			27,683			27,683
				1,606				595,772			27,683			625,061
	OPEB assets
	Mutual funds			38,540				-			-			38,540
				38,540				-			-			38,540

	Fair value of plan assets, December 31, 2012		$	40,146			$	595,772		$	27,683		$	663,601
Schedule of changes in fair value of Level 3 plan assets	'
	The following tables set forth a reconciliation of changes in the fair value of the assets above that are classified as Level 3 in the fair value hierarchy for the twelve month periods ended December 31, 2013 and 2012.

			Year Ended
			31-Dec-13
			(In Thousands)
	Pension assets-Level 3, December 31, 2012		$	27,683
	Unrealized/Realized gains and (losses), net			2,035
	Purchases			5,113
	Pension assets-Level 3, December 31, 2013		$	34,831

			Year Ended
			31-Dec-12
			(In Thousands)
	Pension assets-Level 3, December 31, 2011		$	-
	Unrealized/Realized gains and (losses), net			479
	Purchases			27,204
	Pension assets-Level 3, December 31, 2012		$	27,683

QUARTERLY_FINANCIAL_DATA_UNAUD1

QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	Dec. 31, 2013
QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]	'
Schedule of Quarterly Financial Data	'
	Selected quarterly financial data for 2013 and 2012 are set forth below:

			1^st		2^nd		3rd		4^th
			Quarter		Quarter		Quarter		Quarter
	(In Thousands, Except Per Share Amounts)
	2013
	Operating Revenues		$	548,039	$	319,074	$	316,478	$	435,125
	Operating Income		$	96,233	$	43,235	$	22,659	$	78,362
	Net Income		$	51,807	$	17,934	$	5,157	$	40,419
	Net Income attributable to UIL Holdings		$	51,791	$	17,924	$	5,144	$	40,406

	Earnings Per Share of Common Stock – Basic: (1)		$	1.02	$	0.35	$	0.1	$	0.71

	Earnings Per Share of Common Stock – Diluted: (1)		$	1.01	$	0.35	$	0.1	$	0.71

	2012
	Operating Revenues		$	457,818	$	282,842	$	322,888	$	422,953
	Operating Income		$	87,461	$	36,507	$	39,126	$	67,496
	Net Income		$	47,076	$	12,012	$	15,775	$	28,838
	Net Income attributable to UIL Holdings		$	47,050	$	11,999	$	15,749	$	28,839

	Earnings Per Share of Common Stock – Basic: (1)		$	0.93	$	0.24	$	0.31	$	0.57

	Earnings Per Share of Common Stock – Diluted: (1)		$	0.92	$	0.23	$	0.31	$	0.56

	-1	Based on weighted average number of shares outstanding each quarter. Diluted earnings per share reflects the effect of dilutive stock options, performance shares and restricted stock. Quarterly per share amounts are not intended to be additive.

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	12 Months Ended
SEGMENT INFORMATION (Tables)	Dec. 31, 2013
SEGMENT INFORMATION [Abstract]	'
Reconciliation of Operating Profit (Loss) From Segments to Consolidated Financial Statements	'
	UIL Holdings is organized into Electric Distribution, Electric Transmission and Gas Distribution reporting segments based on several factors including, but not limited to, the nature of each segment’s products and services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates. The following measures of segment profit and loss are utilized by management to make decisions about allocating resources to the segments and assessing performance. The following table reconciles certain segment information with that provided in UIL Holdings’ Consolidated Financial Statements. In the table, distribution includes all electric utility revenue and expenses except for transmission, which is provided in a separate column. “Other” includes the information for the remainder of UIL Holdings’ non‑utility activities and unallocated corporate costs, including minority interest investments and administrative costs. Revenues from inter‑segment transactions are not material. All of UIL Holdings’ revenues are derived in the United States.

	(In Thousands)
			31-Dec-13
			Electric Distribution and Transmission
			Distribution			Transmission			Total			Gas Distribution				Other				Total
	Operating Revenues		$	560,877		$	242,681		$	803,558		$	815,023			$	135			$	1,618,716
	Purchased power and gas			139,135			-			139,135			438,189				-				577,324
	Operation and maintenance			189,378			45,540			234,918			154,418				(5,307	)			384,029
	Transmission wholesale			-			88,206			88,206			-				-				88,206
	Depreciation and amortization			91,670			16,353			108,023			77,890				3,943				189,856
	Taxes - other than income taxes			49,421			33,991			83,412			46,477				569				130,458
	Regulatory disallowances			8,354			-			8,354			-				-				8,354
	Operating Income			82,919			58,591			141,510			98,049				930				240,489

	Other Income and (Deductions), net			13,335			4,874			18,209			(323	)			2,747				20,633

	Interest Charges, net			27,052			12,046			39,098			28,935				23,736				91,769

	Income from Equity Investments			15,272			-			15,272			-				-				15,272

	Income (Loss) Before Income Taxes			84,474			51,419			135,893			68,791				(20,059	)			184,625

	Income Taxes			37,816			17,784			55,600			23,309				(9,601	)			69,308
	Net Income (Loss)			46,658			33,635			80,293			45,482				(10,458	)			115,317
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			52				-				52
	Net Income (Loss) attributable to UIL Holdings		$	46,658		$	33,635		$	80,293		$	45,430			$	(10,458	)		$	115,265

	Total Capital Expenditures (1)		$	-		$	-		$	160,042		$	97,346			$	47,790			$	305,178

	(In Thousands)
			31-Dec-12
			Electric Distribution and Transmission
			Distribution			Transmission			Total			Gas Distribution				Other				Total
	Operating Revenues		$	561,148		$	222,314		$	783,462		$	702,887			$	152			$	1,486,501
	Purchased power and gas			154,546			-			154,546			370,234				-				524,780
	Operation and maintenance			178,862			43,185			222,047			137,707				(3,477	)			356,277
	Transmission wholesale			-			79,469			79,469			-				-				79,469
	Depreciation and amortization			88,672			14,890			103,562			75,205				2,581				181,348
	Taxes - other than income taxes			44,845			26,773			71,618			42,254				165				114,037
	Operating Income			94,223			57,997			152,220			77,487				883				230,590

	Other Income and (Deductions), net			16,562			3,945			20,507			4,071				668				25,246

	Interest Charges, net			28,308			12,941			41,249			28,001				23,292				92,542

	Income from Equity Investments			15,273			-			15,273			-				-				15,273

	Income (Loss) Before Income Taxes			97,750			49,001			146,751			53,557				(21,741	)			178,567

	Income Taxes			45,091			17,025			62,116			21,305				(8,555	)			74,866
	Net Income (Loss)			52,659			31,976			84,635			32,252				(13,186	)			103,701
	Less:
	Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			64				-				64
	Net Income (Loss) attributable to UIL Holdings		$	52,659		$	31,976		$	84,635		$	32,188			$	(13,186	)		$	103,637

	Total Capital Expenditures (1)		$	-		$	-		$	178,107		$	80,837			$	29,689			$	288,633

			31-Dec-11
			Electric Distribution and Transmission
			Distribution			Transmission			Total			Gas Distribution				Other				Total
	Operating Revenues		$	599,153		$	198,503		$	797,656		$	772,315			$	123			$	1,570,094
Purchased power and gas			180,149			-			180,149			429,079				-				609,228
Operation and maintenance			216,361			32,027			248,388			133,126				300				381,814
Transmission wholesale			-			77,997			77,997			-				-				77,997
Depreciation and amortization			83,725			12,690			96,415			70,694				353				167,462
Taxes - other than income taxes			45,967			24,736			70,703			43,494				14				114,211
Operating Income (Loss)			72,951			51,053			124,004			95,922				(544	)			219,382

Other Income and (Deductions), net			14,697			6,651			21,348			6,571				(987	)			26,932

Interest Charges, net			30,489			13,235			43,724			28,939				22,722				95,385

Income from Equity Investments			11,282			-			11,282			-				-				11,282

Income (Loss) Before Income Taxes			68,441			44,469			112,910			73,554				(24,253	)			162,211
Income Taxes			30,865			13,186			44,051			29,721				(11,271	)			62,501
Net Income (Loss)			37,576			31,283			68,859			43,833				(12,982	)			99,710
Less:
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests			-			-			-			54				-				54
Net Income (Loss) attributable to UIL Holdings		$	37,576		$	31,283		$	68,859		$	43,779			$	(12,982	)		$	99,656

Total Capital Expenditures (1)		$	-		$	-		$	247,563		$	60,349			$	20,167			$	328,079
Reconciliation of Total Assets from Segments to Consolidated Financial Statements	'
			Electric Distribution and Transmission (2)
			Distribution			Transmission			Total			Gas Distribution (3)				Other				Total
	Total Assets at December 31, 2013		$	-		$	-		$	2,950,707		$	2,010,246			$	183,267			$	5,144,220

	-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
	-2	Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2013, was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.
	-3	Includes $266.2 million of goodwill in the Gas Distribution segment as of December 31, 2013.

			Electric Distribution and Transmission (2)
			Distribution			Transmission			Total			Gas Distribution (3)				Other				Total (3)
	Total Assets at December 31, 2012		$	-		$	-		$	2,935,562		$	1,993,560			$	90,042			$	5,019,164
			Electric Distribution and Transmission (2)
			Distribution			Transmission			Total			Gas Distribution (3)				Other				Total (3)
	Total Assets at December 31, 2011		$	-		$	-		$	2,716,460		$	1,953,079			$	75,070			$	4,744,609

	-1	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.
	-2	Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2012, was $1,114.2 million and $612.0 million for Distribution and Transmission, respectively. As of December 31, 2011, net plant in service was $1,029.8 million and $495.8 million for Distribution and Transmission, respectively.
	-3	Includes $266.8 million of goodwill in the Gas Distribution segment as of December 31, 2012 and 2011.

STATEMENT_OF_ACCOUNTING_POLICI3

STATEMENT OF ACCOUNTING POLICIES (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Basis of Presentation [Abstract]	'	'	'
Property, Plant and Equipment, Net	$3,068,680	$2,847,151	'
Regulatory Liability, Noncurrent	445,092	504,953	'
Accounts Payable, Current	164,416	189,991	'
Accrued Liabilities, Current	78,125	85,132	'
Ownership percentage in GenConn [Abstract]	'	'	'
Ownership percentage in joint venture (in hundredths)	50.00%	'	'
Allowance for Funds Used During Construction [Abstract]	'	'	'
Weighted-average allowance for funds used during construction (in hundredths)	9.63%	5.61%	5.75%
Annual depreciation rate (in hundredths)	3.40%	3.50%	3.30%
Asset Retirement Obligations Activity [Abstract]	'	'	'
Beginning Balance	18,289	18,058	'
Liabilities incurred during the year	0	0	'
Liabilities settled during the year	-740	-718	'
Accretion	961	949	'
Ending Balance	18,510	18,289	18,058
Restatement Adjustment [Member]	'	'	'
Basis of Presentation [Abstract]	'	'	'
Property, Plant and Equipment, Net	'	59,800	'
Regulatory Liability, Noncurrent	'	59,800	'
Accounts Payable, Current	'	13,100	'
Accrued Liabilities, Current	'	($13,100)	'

STATEMENT_OF_ACCOUNTING_POLICI4

STATEMENT OF ACCOUNTING POLICIES, DERIVATIVES, EARNINGS PER SHARE (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Sep. 30, 2013

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2013

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2013

Dec. 31, 2012

CapacityResources

Current Assets [Member]

Deferred Charges and Other Assets [Member]

Current Liabilities [Member]

Noncurrent Liabilities [Member]

Weather Insurance Contracts [Member]

Southern Connecticut Gas Company (SCG) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

Berkshire [Member]

Derivative [Line Items]

Gross derivative asset

$53,400,000

$9,098,000

$12,671,000

$44,349,000

$67,167,000

Regulatory asset

142,700,000

Gross derivative liability

196,200,000

26,976,000

30,804,000

169,327,000

224,639,000

Gross derivative liability, UIL's portion of entity

129,400,000

Payment received under weather insurance contract

1,000,000

Maximum receivable amount allowed under weather insurance contract

3,000,000

3,000

1,500,000

3,000,000

1,000,000

Maximum payable amount allowed under weather insurance contract

2,000,000

2,000

1,000,000

2,000,000

200,000

Intrinsic value of contract

100,000

1,000,000

Derivatives [Abstract]

Number of new capacity resources selected

Number of Contracts for Differences (CfDs) approved by Public Utility Regulatory Authority (PURA)

Number of Contracts for Differences (CfDs) executed by UI

Number of Contracts for Differences (CfDs) executed by CL&P

Percentage of cost or benefit borne by or allocated to UI customers for CFDs (in hundredths)

20.00%

Percentage of cost or benefit borne by or allocated to CL&P customers (in hundredths)

80.00%

Unrealized gain and losses from mark-to-market adjustments [Abstract]

Regulatory Assets - Derivative liabilities

-33,819,000

-7,500,000

Regulatory Liabilities - Derivative assets

12,000

Numerator [Abstract]

Net income attributable to UIL Holdings

40,406,000

5,144,000

17,924,000

51,791,000

28,839,000

15,749,000

11,999,000

47,050,000

115,265,000

103,637,000

99,656,000

Less: Net income allocated to unvested units

117,000

184,000

210,000

Net income attributable to common shareholders

$115,148,000

$103,453,000

$99,446,000

Denominator [Abstract]

Basic average number of shares outstanding (in shares)

52,415,000

50,831,000

50,609,000

Effect of dilutive securities (in shares)

296,000

277,000

317,000

Diluted average number of shares outstanding (in shares)

52,711,000

51,108,000

50,926,000

Earnings per share [Abstract]

Basic (in dollars per share)

$0.71

[1]

$0.10

[1]

$0.35

[1]

$1.02

[1]

$0.57

[1]

$0.31

[1]

$0.24

[1]

$0.93

[1]

$2.20

$2.04

$1.96

Diluted (in dollars per share)

$0.71

[1]

$0.10

[1]

$0.35

[1]

$1.01

[1]

$0.56

[1]

$0.31

[1]

$0.23

[1]

$0.92

[1]

$2.18

$2.02

$1.95

Number of shares of common stock outstanding with purchase options not included in diluted earnings per share (in shares)

89,336

[1]

Based on weighted average number of shares outstanding each quarter. Diluted earnings per share reflects the effect of dilutive stock options, performance shares and restricted stock. Quarterly per share amounts are not intended to be additive.

STATEMENT_OF_ACCOUNTING_POLICI5

STATEMENT OF ACCOUNTING POLICIES, PROPERTY, PLANT AND EQUIPMENT, EQUITY INVESTMENTS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity Investments [Abstract]	'	'	'
Income (loss) from equity investment	$15,272,000	$15,273,000	$11,282,000
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	3,691,760,000	3,429,575,000	'
Less accumulated depreciation	944,399,000	893,764,000	'
Total	2,747,361,000	2,535,811,000	'
Construction work in progress	321,319,000	311,340,000	'
Net Property, Plant and Equipment	3,068,680,000	2,847,151,000	'
Electric Distribution Plant [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	979,526,000	860,096,000	'
Electric Transmission Plant [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	630,834,000	577,669,000	'
Gas Distribution Plant [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	1,444,837,000	1,386,288,000	'
Software [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	144,494,000	136,219,000	'
Building Improvements [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	235,002,000	220,821,000	'
Land [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	64,848,000	64,421,000	'
Other Plant [Member]	'	'	'
Property, plant and equipment [Abstract]	'	'	'
Gross property, plant, & equipment	192,219,000	184,061,000	'
GenConn [Member]	'	'	'
Equity Investments [Abstract]	'	'	'
Carrying value of joint venture	118,200,000	124,800,000	'
Income (loss) from equity investment	15,300,000	15,300,000	11,300,000
Distributions received from joint venture	21,800,000	21,500,000	8,000,000
Undistributed earnings in equity method investment	$100,000	'	'
Number of peaking generation plants	2	'	'

STATEMENT_OF_ACCOUNTING_POLICI6

STATEMENT OF ACCOUNTING POLICIES, REGULATORY ASSETS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	$1,036,130,000		$1,135,450,000
Asset decoupling amount	11,600,000		'
Less current portion of regulatory assets	332,391,000		120,935,000
Regulatory Assets, Net	703,739,000		1,014,515,000
Nuclear Plant Investments - Above Market [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	238,868,000	[1]	252,498,000	[1]
Connecticut Yankee [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	0		11,129,000
Unamortized Redemption Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	11,301,000		12,103,000
Remaining period, minimum	'8 years		'
Remaining period, maximum	'20 years		'
Pension and Other Post-Retirement Benefit Plans [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	316,076,000	[2]	458,019,000	[2]
Environmental Remediation Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	14,953,000		14,772,000
Remaining period	'3 years		'
Hardship Programs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	25,019,000	[3]	29,852,000	[3]
Debt Premium [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	34,178,000		41,016,000
Remaining period, minimum	'1 year		'
Remaining period, maximum	'24 years		'
Deferred Purchased Gas [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	2,556,000	[4]	12,444,000	[4]
Income Taxes Due Principally to Book-tax Differences [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	149,015,000	[5]	0	[5]
Deferred Income Taxes [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	861,000	[6]	0	[6]
Unfunded Future Income Taxes [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	31,656,000	[6]	17,319,000	[6]
Contracts For Differences [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	142,743,000	[7]	176,597,000	[7]
Term of contract minimum	'6 years		'
Term of contact maximum	'13 years		'
Excess Generation Service Charge [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	6,909,000	[8]	8,864,000	[8]
Deferred Transmission Expense [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	9,615,000	[9]	21,379,000	[9]
Storm Costs [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	14,752,000	[10]	52,009,000	[10]
Other Regulatory Asset [Member]	'		'
Regulatory Assets [Line Items]	'		'
Total Regulatory Assets	$37,628,000	[11]	$27,449,000	[11]

[1]	Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UIbs 2013 distribution rate request, PURA approved UIbs proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet as of December 31, 2013.
[2]	Life is dependent upon timing of final pension plan distribution; balance, which is fully offset by a corresponding asset/liability, is recalculated each year in accordance with ASC 715 "Compensation-Retirement Benefits." See Note (G) bPension and Other Benefitsb for additional information.
[3]	Hardship customer accounts deferred for future recovery to the extent they exceed the amount in rates.
[4]	Deferred purchase gas costs balances at the end of the rate year are normally recorded/returned in the next year.
[5]	Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA. In prior periods, these amounts were presented on a net basis in long-term regulatory liabilities. In the current period, due to the end of the CTA charge, the CTA regulatory liabilities have been reclassified to current regulatory liabilities and the regulatory assets not related to the CTA have been reclassified to long-term regulatory assets.
[6]	The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
[7]	Asset life is equal to delivery term of related contracts (which vary from approximately 6 - 13 years); balance fluctuates based upon quarterly market analysis performed on the related derivatives (Note K); amount, which does not earn a return, is fully offset by corresponding derivative asset/liability. See b-Contracts for Differencesb discussion above for additional information.
[8]	Working capital allowance for generation service charge; this amount fluctuates based upon cash inflows and outflows in a given period.
[9]	Regulatory asset or liability which defers transmission income or expense and fluctuates based upon actual revenues and revenue requirements.
[10]	Storm costs include accumulated costs for major storms occurring from January 2009 forward. See Note (C) bRegulatory Proceedings b Electric Distribution and Transmission b Ratesb for a discussion of the recovery of these costs.
[11]	Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($11.6 million) and certain other amounts that are not currently earning a return. See Note (C) bRegulatory Proceedings b Electric Distribution and Transmission b Ratesb for a discussion of the decoupling recovery period.

STATEMENT_OF_ACCOUNTING_POLICI7

STATEMENT OF ACCOUNTING POLICIES, REGULATORY LIABILITIES (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	$706,821		$526,237
Less current portion of regulatory liabilities	261,729		21,284
Regulatory Liabilities, Net	445,092		504,953
Accumulated Deferred Investment Tax Credits [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	4,465		4,612
Remaining period	'30 years		'
Income Taxes Due Principally To Book Tax Differences Liabilities [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	200,673	[1]	41,928	[1]
Deferred Gain on Sale of Property [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	37,933	[2]	37,933	[2]
Middletown/Norwalk Local Transmission Network Service Collections [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	21,402		21,975
Remaining period	'36 years		'
Pension And Other Post-Retirement Benefit Plans [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	27,686		15,016
Remaining period	'6 years		'
Deferred Income Taxes [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	43,421	[3]	41,816	[3]
Asset Retirement Obligation [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	5,593	[4]	4,995	[4]
Low Income Program [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	25,300	[5]	17,651	[5]
Asset Removal Costs [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	319,530	[6]	303,651	[6]
Other Regulatory Liability [Member]	'		'
Regulatory Liabilities [Line Items]	'		'
Total regulatory liabilities	$20,818	[6]	$36,660	[6]

[1]	Amortization period and/or balance vary depending on the nature and/or remaining life of the underlying assets/liabilities; balances contain regulatory liabilities related to the CTA as well as regulatory assets not related to the CTA. In prior periods, these amounts were presented on a net basis in long-term regulatory liabilities. In the current period, due to the end of the CTA charge, the CTA regulatory liabilities have been reclassified to current regulatory liabilities and the regulatory assets not related to the CTA have been reclassified to long-term regulatory assets.
[2]	Asset/Liability relates to the Competitive Transition Assessment (CTA). Total CTA costs recovery and stranded cost amortization are complete. The remaining balances are fully offset by amounts primarily included in income taxes, due principally to book-tax differences. As a result of the outcome of UIbs 2013 distribution rate request, PURA approved UIbs proposed rate treatment to leave CTA rates unchanged until January 1, 2014 at which point the charge ended. The remaining balances will be extinguished upon the completion of the final reconciliation hearing in 2014 and have been reclassified to current regulatory assets and liabilities on the balance sheet as of December 31, 2013.
[3]	The balance will be extinguished when the asset, which is fully offset by a corresponding liability, or liability has been realized or settled, respectively.
[4]	The liability will be extinguished simultaneous with the retirement of the assets and settlement of the corresponding asset retirement obligation.
[5]	Various hardship and payment plan programs approved for recovery.
[6]	Amortization period and/or balance vary depending on the nature, cost of removal and/or remaining life of the underlying assets/liabilities; asset amount includes decoupling ($11.6 million) and certain other amounts that are not currently earning a return. See Note (C) bRegulatory Proceedings b Electric Distribution and Transmission b Ratesb for a discussion of the decoupling recovery period.

STATEMENT_OF_ACCOUNTING_POLICI8

STATEMENT OF ACCOUNTING POLICIES, RESTRICTED CASH AND STOCK-BASED COMPENSATION (Details) (USD $)	12 Months Ended					1 Months Ended		12 Months Ended	1 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2013	31-May-13	Mar. 31, 2013	Dec. 31, 2013	31-May-13	Mar. 31, 2013	31-May-13
				Restricted Stock [Member]	Performance Shares [Member]	Non-Employee Directors [Member]	President and Chief Executive Officer [Member]	President and Chief Executive Officer [Member]	Management [Member]	Management [Member]	Other Executive Officer [Member]
						Restricted Stock [Member]	Restricted Stock [Member]	Restricted Stock [Member]	Performance Shares [Member]	Performance Shares [Member]	Restricted Stock [Member]
Restricted cash [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Restricted cash	$2	$2.80	'	'	'	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Performance measurement period	'	'	'	'	'3 years	'	'	'	'	'	'
Vesting period	'	'	'	'	'3 years	'	'	'5 years	'	'	'
Number of shares granted (in shares)	'	'	'	25,768	107,010	21,558	2,033	'	5,860	101,150	2,177
Weighted average grant date fair value (in dollars per share)	'	'	'	$40.59	$38.87	$40.69	$38.73	'	$41.34	$38.73	$41.34
Vesting rights	'	'	'	'	'	'	'	'equal annual installments over a five year period	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	4,150,000	'	'	'	'	'	'	'	'	'	'
Total stock-based compensation expense	$5.30	$4.90	$5.30	'	'	'	'	'	'	'	'

CAPITALIZATION_Details

CAPITALIZATION (Details) (USD $)	12 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Feb. 03, 2014
	Common Stock [Member]	Common Stock [Member]	CNG, 8.00% Noncallable [Member]	CNG, 8.00% Noncallable [Member]
				Subsequent Event [Member]
Equity [Line Items]	'	'	'	'
Common stock outstanding (in shares)	56,462,507	50,665,114	'	'
Common stock par value (in dollars per share)	$0	$0	'	'
Proceeds from Issuance of Common Stock	$206.40	'	'	'
Preferred Stock of Subsidiaries, Noncontrolling Interests [Abstract]	'	'	'	'
Dividend rate of preferred stock (in hundredths)	'	'	8.00%	'
Par value per share (in dollars per share)	'	'	$3.13	'
Shares issued and outstanding (in shares)	'	'	108,706	'
Value of shares issued and outstanding	'	'	$0.30	'
Stock authorized but unissued (in shares)	'	'	775,609	'
Offering price in purchase of preferred shares (in dollars per share)	'	'	'	$7.50
Common stock shares issued (in shares)	5,750,000	'	'	'
Common stock offering price (in dollars per share)	$37.25	'	'	'
Over-allotment option for underwriters (in shares)	750,000	'	'	'

CAPITALIZATION_Sharebased_Comp

CAPITALIZATION, Share-based Compensation (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Average exercise price [Abstract]	'	'	'
Weighted-average remaining contractual life	'	'0 years 3 months 18 days	'0 years 6 months
Restricted Stock [Member]	'	'	'
Number of shares [Abstract]	'	'	'
Beginning Balance (in shares)	74,131	'	'
Granted (in shares)	25,768	'	'
Forfeited (in shares)	-1,672	'	'
Vested (in shares)	-67,307	'	'
Ending Balance (in shares)	30,920	'	'
Weighted average grant date fair value [Abstract]	'	'	'
Beginning Balance (in dollars per share)	$30.49	'	'
Granted (in dollars per share)	$40.59	'	'
Forfeited (in dollars per share)	$29.91	'	'
Vested (in dollars per share)	$30.50	'	'
Ending Balance (in dollars per share)	$38.90	'	'
Restricted stock [Abstract]	'	'	'
Restricted stock (in shares)	276,845	209,469	'
Average exercise price [Abstract]	'	'	'
Unrecognized costs for stock awards	$0.50	'	'
Weighted-average period for cost recognition	'9 months	'	'
Performance Shares [Member]	'	'	'
Number of shares [Abstract]	'	'	'
Beginning Balance (in shares)	325,888	'	'
Granted (in shares)	107,010	'	'
Forfeited (in shares)	-36,740	'	'
Vested (in shares)	-61,150	'	'
Ending Balance (in shares)	335,008	'	'
Weighted average grant date fair value [Abstract]	'	'	'
Beginning Balance (in dollars per share)	$31.39	'	'
Granted (in dollars per share)	$38.87	'	'
Vested (in dollars per share)	$28.53	'	'
Ending Balance (in dollars per share)	$34.62	'	'
Average exercise price [Abstract]	'	'	'
Unrecognized costs for stock awards	2.1	'	'
Weighted-average period for cost recognition	'11 months	'	'
Performance Shares and Restricted Stock [Member]	'	'	'
Weighted average grant date fair value [Abstract]	'	'	'
Weighted average grant date fair value (in dollars per share)	$39.21	$34.33	$33.33
Stock Options [Member]	'	'	'
Number of options [Roll Forward]	'	'	'
Beginning balance (in shares)	3,333	98,220	134,994
Granted (in shares)	0	0	0
Forfeited (in shares)	0	-38,000	-7,910
Exercised (in shares)	-3,333	-56,887	-28,864
Ending balance (in shares)	0	3,333	98,220
Option price per share [Abstract]	'	'	'
Beginning balance, minimum (in dollars per share)	$21.68	$21.68	$21.68
Beginning balance, maximum (in dollars per share)	$21.68	$33.96	$34.51
Exercised, minimum (in dollars per share)	$21.68	$31.25	$21.68
Exercised, maximum (in dollars per share)	$21.68	$33.96	$31.25
Ending balance, minimum (in dollars per share)	'	$21.68	$21.68
Ending balance, maximum (in dollars per share)	'	$21.68	$33.96
Average exercise price [Abstract]	'	'	'
Beginning balance (in dollars per share)	$21.68	$33.39	$31.70
Ending balance (in dollars per share)	'	$21.68	$33.39
Number of exercisable stock options (in shares)	0	3,333	98,220
Option price per share, minimum (in dollars per share)	'	$21.68	$21.68
Option price per share, maximum (in dollars per share)	'	$21.68	$33.96
Average exercisable at end of period (in dollars per share)	'	$21.68	$33.39
Cash received from options exercised under all share-based payment arrangements	0.1	1.9	0.8
Tax benefit realized for the tax deductions from the option exercises	$0.10	$0.10	$0.10

CAPITALIZATION_Longterm_Debt_D

CAPITALIZATION, Long-term Debt (Details) (USD $)	12 Months Ended
CAPITALIZATION, Long-term Debt (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Long-term debt [Abstract]	'		'		'
Long-term debt	$1,704,095,000		$1,610,550,000		'
Less: Current portion of long-term debt	11,834,000	[1]	48,296,000	[1]	'
Less: Unamortized discount	2,597,000		2,916,000		'
Plus: Unamortized premium	34,178,000		41,016,000		'
Net Long-Term Debt	1,723,842,000		1,600,354,000		'
Interest rate on tax-exempt bond (in hundredths)	0.34%		'		'
Restricted net assets	557,200,000		'		'
Auction rate interest rate reset period	'35 days		'		'
Discounted net proceed from note issued	135,000,000		203,500,000		51,050,000
Fair value long-term debt	1,800,000,000		1,900,000,000		'
Weighted average maturity term of long-term debt	'11 years 8 months 12 days		'		'
Long term debt average interest (in hundredths)	5.44%		'		'
Maturities [Abstract]	'		'		'
2014	6,455,000		'		'
2015	1,455,000		'		'
2016	11,455,000		'		'
2017	91,455,000		'		'
2018 & thereafter	1,593,275,000		'		'
Series C Senior Notes Due 2022 [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Principal amount of note outstanding	34,000,000		'		'
Series C Senior Notes Due 2022 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	3.61%		'		'
Due date	'January 31, 2022		'		'
Series E Senior Notes Due 2042 [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	4.89%		'		'
Principal amount of note outstanding	35,000,000		'		'
Due date	'January 30, 2042		'		'
United Illuminating Company (UI) [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Restricted net assets, UI equity investment	118,200,000		'		'
Maturities [Abstract]	'		'		'
Amount of note purchase agreement	203,500,000		'		'
Remaining amount of note purchase agreement	100,000,000		'		'
United Illuminating Company (UI) [Member] \| Pollution Control Revenue Bonds [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Bonds refinanced, aggregate principle amount outstanding	103,500,000		'		'
United Illuminating Company (UI) [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Discounted net proceed from note issued	103,500,000		'		'
United Illuminating Company (UI) [Member] \| Series A Senior Notes Due 2018 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	6.46%		'		'
Due date	'2018		'		'
United Illuminating Company (UI) [Member] \| Series A Senior Notes Due 2019 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	31,000,000		31,000,000		'
Interest rate (in hundredths)	2.98%		'		'
Due date	'2019		'		'
Principal amount of note outstanding	31,000,000		'		'
Due date	'January 31, 2019		'		'
United Illuminating Company (UI) [Member] \| Series A and B Senior Notes Due 2018 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	100,000,000		100,000,000		'
United Illuminating Company (UI) [Member] \| Series B Senior Notes Due 2018 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	6.51%		'		'
Due date	'2018		'		'
United Illuminating Company (UI) [Member] \| 2010 Series Due 2027 [Member] \| Pollution Control Revenue Bonds [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	27,500,000		27,500,000		'
Interest rate (in hundredths)	4.50%		'		'
Due date	'2027		'		'
United Illuminating Company (UI) [Member] \| 2003 Series Due 2033 [Member] \| Pollution Control Revenue Bonds [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	64,460,000	[2]	64,460,000	[2]	'
Interest rate, other	'Auction Rate		'		'
Due date	'2033		'		'
United Illuminating Company (UI) [Member] \| Series A and B Senior Notes Due 2017 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	70,000,000		70,000,000		'
Interest rate (in hundredths)	6.06%		'		'
Due date	'2017		'		'
United Illuminating Company (UI) [Member] \| Series C and D Senior Notes Due 2022 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	6.26%		'		'
Due date	'2022		'		'
United Illuminating Company (UI) [Member] \| Series E and F Senior Notes Due 2037 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	28,000,000		28,000,000		'
Interest rate (in hundredths)	6.51%		'		'
Due date	'2037		'		'
United Illuminating Company (UI) [Member] \| Series C Senior Notes Due 2020 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	50,000,000		50,000,000		'
Interest rate (in hundredths)	6.61%		'		'
Due date	'2020		'		'
United Illuminating Company (UI) [Member] \| Senior Notes Due 2040 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	100,000,000		100,000,000		'
Interest rate (in hundredths)	6.09%		'		'
Due date	'2040		'		'
United Illuminating Company (UI) [Member] \| Series D and E Senior Notes Due 2042 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	87,000,000		87,000,000		'
Interest rate (in hundredths)	4.89%		'		'
Due date	'2042		'		'
United Illuminating Company (UI) [Member] \| Series B and C Senior Notes [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	3.61%		'		'
Due date	'2022		'		'
United Illuminating Company (UI) [Member] \| Series B, C and D Senior Notes Due 2022 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	162,500,000		162,500,000		'
United Illuminating Company (UI) [Member] \| Series D Senior Note Due 2042 [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	4.89%		'		'
Principal amount of note outstanding	52,000,000		'		'
Due date	'January 30, 2042		'		'
United Illuminating Company (UI) [Member] \| Senior Notes Due 2025 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	50,000,000		50,000,000		'
Interest rate (in hundredths)	5.61%		'		'
Due date	'2025		'		'
United Illuminating Company (UI) [Member] \| Series B Senior Unsecured Notes due 2022 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Interest rate (in hundredths)	3.61%		'		'
Principal amount of note outstanding	51,500,000		'		'
Due date	'January 31, 2022		'		'
United Illuminating Company (UI) [Member] \| Series F Senior Note Due 2023 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	75,000,000		0		'
Interest rate (in hundredths)	3.95%		'		'
Due date	'2023		'		'
UIL Holdings [Member] \| Unsecured Senior Notes Due 2020 [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	450,000,000		450,000,000		'
Interest rate (in hundredths)	4.63%		'		'
Due date	'2020		'		'
Gas Companies [Member] \| Senior Unsecured Notes Due 2020 - 2021 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	19,635,000		21,090,000		'
Interest rate, minimum (in hundredths)	4.76%		'		'
Interest rate, maximum (in hundredths)	9.60%		'		'
Due date, minimum	'2020		'		'
Due date, maximum	'2021		'		'
Gas Companies [Member] \| Secured Medium Term Note IV, Due 2018-2041 [Member] \| Secured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	100,000,000		100,000,000		'
Interest rate, minimum (in hundredths)	3.88%		'		'
Interest rate, maximum (in hundredths)	7.50%		'		'
Due date, minimum	'2018		'		'
Due date, maximum	'2041		'		'
Gas Companies [Member] \| Secured Medium Term Notes III, Due 2025-2037 [Member] \| Secured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	85,000,000		85,000,000		'
Interest rate, minimum (in hundredths)	5.77%		'		'
Interest rate, maximum (in hundredths)	6.38%		'		'
Due date, minimum	'2025		'		'
Due date, maximum	'2037		'		'
Gas Companies [Member] \| Secured Medium Term Notes I, Due 2026-2028 [Member] \| Secured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	29,000,000		29,000,000		'
Interest rate, minimum (in hundredths)	6.88%		'		'
Interest rate, maximum (in hundredths)	7.95%		'		'
Due date, minimum	'2026		'		'
Due date, maximum	'2028		'		'
Gas Companies [Member] \| First Mortgage Bond Series P Due 2019 [Member] \| Secured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	10,000,000		10,000,000		'
Interest rate (in hundredths)	10.06%		'		'
Due date	'2019		'		'
Gas Companies [Member] \| Series A Unsecured Medium Term Notes Due 2013-2017 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	30,000,000		50,000,000		'
Interest rate, minimum (in hundredths)	6.85%		'		'
Interest rate, maximum (in hundredths)	9.10%		'		'
Due date, minimum	'2013		'		'
Due date, maximum	'2017		'		'
Gas Companies [Member] \| Series D Unsecured Medium Term Notes Due 2013 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	0		20,000,000		'
Interest rate (in hundredths)	6.50%		'		'
Due date	'2013		'		'
Gas Companies [Member] \| Series B Unsecured Medium Term Notes Due 2014-2024 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	10,000,000		10,000,000		'
Interest rate, minimum (in hundredths)	8.12%		'		'
Interest rate, maximum (in hundredths)	8.49%		'		'
Due date, minimum	'2014		'		'
Due date, maximum	'2024		'		'
Gas Companies [Member] \| Series C Unsecured Medium Term Notes Due 2035-2037 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	65,000,000		65,000,000		'
Interest rate, minimum (in hundredths)	5.63%		'		'
Interest rate, maximum (in hundredths)	6.66%		'		'
Due date, minimum	'2035		'		'
Due date, maximum	'2037		'		'
Gas Companies [Member] \| Series D Medium Term Note Due 2028 - 2043 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	45,000,000		0		'
Interest rate, minimum (in hundredths)	4.30%		'		'
Interest rate, maximum (in hundredths)	5.23%		'		'
Due date, minimum	'2028		'		'
Due date, maximum	'2043		'		'
Gas Companies [Member] \| Series A Senior Note Due 2043 [Member] \| Unsecured Notes [Member]	'		'		'
Long-term debt [Abstract]	'		'		'
Long-term debt payable	$15,000,000		$0		'
Interest rate (in hundredths)	5.33%		'		'
Due date	'2043		'		'

[1]	Includes the current portion of unamortized premium.
[2]	On December 31, 2013, the interest rate on the Bonds was 0.34%. The interest rate on these Bonds is reset through an auction held every 35 days.

REGULATORY_PROCEEDINGS_Details

REGULATORY PROCEEDINGS (Details) (Superstorm Sandy [Member], USD $)	Dec. 31, 2013
In Millions, unless otherwise specified	Customer
Superstorm Sandy [Member]	'
Catastrophic Event [Line Items]	'
Approximate number of customer outages	284,000
Estimate of costs to repair damages	$35.80
Estimate of costs to repair damages, amount capitalized	$13.90

REGULATORY_PROCEEDINGS_PART_TW

REGULATORY PROCEEDINGS, PART TWO (Details) (USD $)

1 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

Feb. 15, 2013

Dec. 31, 2013

Dec. 16, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Feb. 07, 2014

Aug. 13, 2013

Feb. 28, 2013

Sep. 30, 2012

Jul. 08, 2013

Jun. 14, 2013

Dec. 31, 2013

Jun. 14, 2013

Dec. 31, 2013

Contract

Gas Supply Arrangements [Member]

United Illuminating Company (UI) [Member]

Connecticut Natural Gas Corporation (CNG) [Member]

Connecticut Natural Gas Corporation (CNG) and Southern Connecticut Gas Company [Member]

The Southern Connecticut Gas Company (SCG) [Member]

The Berkshire Gas Company [Member]

GenConn Devon [Member]

GenConn Middletown [Member]

Pipeline

Project

Mechanism

Customer

Contractor

Plant

Megawatt

Contract

Facility

Bidder

Plant

Facility

Rates [Abstract]

Length of time for proposed rate amendment

'2 years

Schedule of Regulatory Proceedings [Line Items]

Allowed distribution return on equity (in hundredths)

8.75%

Allowed distribution return on equity per 2013 decision (in hundredths)

9.15%

Earnings share split of profit

'50/50

Disallowance of deferred storm costs and capital costs per PURA final decision in rate case

$22,000,000

Write-off related to disallowance of deferred storm costs and capital costs per PURA final decision in rate case, net of tax

17,500,000

Reversal of write-off related to deferred storm costs and capital costs per PURA final reconsideration decision

9,200,000

Restoration of disallowed deferred storm costs per PURA final decision rate case

6,800,000

Restoration of disallowed capital costs per PURA final decision rate case

2,700,000

Allowed recovery of storm costs, per PURA final decision rate case

45,000,000

Regulatory asset related to storm recovery

14,800,000

Decoupling charge approved by PURA

6,400,000

4,000,000

Decoupling charge to be approved by PURA

900,000

Power Supply Arrangements [Abstract]

Maximum kilowatt allowed for UI to provide power

500

Duration of contracts after reduction

'12 months

Maximum number of months to commence delivery of such wholesale power

'6 months

Percentage of standard service customers with wholesale power supply agreements in place for the first half of 2014 (in hundredths)

100.00%

Percentage of standard service customers with wholesale power supply agreements in place for the second half of 2014 (in hundredths)

80.00%

Collateral required to be posted if the entity's credit rating declined two ratings to fall below investment grade

10,600,000

Percentage of standard service requirements for which long term contracts which can be sought (in hundredths)

20.00%

Transitional Standard Offer Incentive (TSO) [Abstract]

TSO incentive rate (in dollars per KWH)

0.0025

Amount of TSO incentives approved

2,700,000

Approval for issuance of Debt [Abstract]

Principal amount of debt securities DPU approved for issuance

20,000,000

Senior unsecured notes issued

15,000,000

New England East-West Solution [Abstract]

Number of inter related transmission projects

Number of inter-related transmission projects with portions sited in Connecticut

Minimum amount of entity's investment for ownership of specific transmission assets

60,000,000

Threshold percentage of CL&P's costs for the Connecticut portions of projects (in hundredths)

8.40%

Expected amount of investment

60,000,000

Amount of transmission assets

24,600,000

18,400,000

6,200,000

Cumulative amount of deposits

35,100,000

1,000,000

Pre-tax income earned on each deposit in NEEWS project.

1,500,000

1,600,000

1,000,000

Rates [Abstract]

Approved return on equity (in hundredths)

9.18%

9.36%

10.50%

Duration of approved rate plan

'10 years

Number of rate making mechanisms

Earnings share mechanism ratio

'50/50

Number of new customers to be added

280,000

Rate premium for distribution component of on-main customers (in hundredths)

10.00%

Rate premium for distribution component of off-main customers (in hundredths)

30.00%

Transmission Return of Equity (ROE) [Abstract]

Weighted average return on equity (in hundredths)

12.20%

Return on equity sought by complainants

9.20%

Revised return on equity sought by complainants (in hundredths)

8.70%

Current approved base return on equity (in hundredths)

11.14%

ROE adder on pool transmission facilities in basis points

Roe incentive for projects included in the ISO-NE regional system plan in basis points

100

Change in weighted average return on equity in basis points (in hundredths)

0.25%

Reduction in annual net income

600,000

Return on equity per initial decision for refund period of October 1, 2011 through December 31, 2012 (in hundredths)

10.60%

Return on equity, per initial decision, for the period after final opinion issued by FERC (in hundredths)

9.70%

Reserve recorded by UI for refund

2,600,000

Refund period

'P15M

Equity Investment in Peaking Generation [Abstract]

Ratio of equity investment in peaking generation for joint venture

'50-50

Number of peaking generation plants

Revenue requirements for equity investment in peaking generation

30,800,000

37,500,000

New Renewable Source Generation [Abstract]

Maximum amount of commitment to purchase Renewable Energy Credits (RECs) from new facilities behind distribution customer meters

200,000,000

Period of commitment to purchase Renewable Energy Credits (RECs)

'21 years

Solicitation period obligations will phase-in

'6 years

Maximum annual commitment level obligation after year six

13,600,000

Total amount of annual payments related to REC purchase contracts entered into by UI

2,900,000

Delivery terms of REC purchase contracts

'15 years

Number of mega watts of grid connected renewable energy allowed to be developed per Connecticut Public Act 11-80 (in MW)

Number of mega watts of grid connected renewable energy allowed to be developed by each company (in MW)

Amount of grid connected renewable energy solicited by DEEP from market

Number of solar projects selected by DEEP

Mega watts of solar projects selected by DEEP (in MW)

Percentage of cost from contract executed with CL&P (in hundredths)

20.00%

Percentage of benefit from contract executed with CL&P (in hundredths)

20.00%

Renewable generation capacity for recovery (in MW)

Number of solar facilities approved by PURA

Number of fuel cell facilities approved by PURA

Requested ROE by UI

9.50%

Requested ROE by New England transmission owners and UI

8.75%

Basis point added to return on equity (in hundredths)

0.25%

Megawatts of projects for which budget must be submitted within three months

7.8

Megawatts of projects for which budget must be submitted within twelve months

2.2

Percentage of UIs distribution load for which UI may be directed to enter to contracts for energy and/or RECs (in hundredths)

4.00%

Number of winning bidders approved by PURA

Total Megawatts of power purchase agreements pending PURA approval (in MW)

48.1

Energy under power purchase agreements by solar project (in MW)

3.8

Capacity of energy by wind farm (in MW)

250

Capacity of energy by solar project (in MW)

Percentage of UI's distribution load represented by quantity of energy and RECs to be purchased, pending PURA approval

3.50%

Number of long term contracts to purchase RECs from existing biomass facilities

Future Supply Commitments [Line Items]

Number of firm transportation contracts

100

Number of pipelines

Number of pipelines interconnect

Number of gas storage contracts

Number of different storage contractors

Duration to which financial hurdle rate model extended

'25 years

Future obligations under gas supply arrangements [Abstract]

2014

126,485,000

2015

112,665,000

2016

99,467,000

2017

72,369,000

2018

42,609,000

2019-after

72,979,000

Supply obligation total

$526,574,000

SHORTTERM_CREDIT_ARRANGEMENTS_1

SHORT-TERM CREDIT ARRANGEMENTS (Details) (USD $)

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Oct. 31, 2012

Gas Companies [Member]

UIL [Member]

UI [Member]

Standby Letter of Credit Due 2013 [Member]

Standby Letter of Credit Due 2015 [Member]

Revolving Credit Facility [Member]

Credit Agreement [Member]

Non-gas Companies [Member]

UIL [Member]

UI [Member]

CNG [Member]

SNG [Member]

Berkshire [Member]

UIL [Member]

Disclosure of short-term credit arrangements [Abstract]

Available credit under the Credit Facility

$395,600,000

$250,000,000

$150,000,000

$25,000,000

Amounts outstanding under the Credit Facility

Standby letter of credit outstanding

4,400,000

Expiration date

16-Jun-15

30-Nov-16

31-Oct-13

Maximum borrowing capacity

400,000,000

100,000,000

Issuance of letter of credit, maximum

50,000,000

Short-term borrowings [Abstract]

Maximum aggregate principal amount of short-term borrowing outstanding at any month-end

6,000,000

202,000,000

168,000,000

60,000,000

243,000,000

Average aggregate short-term borrowings outstanding during the year

[1]

128,000

[1]

152,455,000

[1]

109,268,000

[1]

13,510,000

[1]

78,533,000

[1]

Weighted average interest rate (in hundredths)

0.00%

[1]

1.59%

[1]

1.43%

[1]

1.61%

[1]

1.40%

[1]

1.58%

[1]

Principal amounts outstanding at year-end

$157,000,000

$30,000,000

[1]

Average shortbterm borrowings represent the sum of daily borrowings outstanding, weighted for the number of days outstanding and divided by the number of days in the period. The weighted average interest rate is determined by dividing interest expense by the amount of average borrowings.

INCOME_TAXES_Details

INCOME TAXES (Details) (USD $)	12 Months Ended
INCOME TAXES (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current	'	'	'
Federal	($443,000)	$5,830,000	($16,626,000)
State	-1,149,000	1,110,000	-3,951,000
Total current	-1,592,000	6,940,000	-20,577,000
Deferred	'	'	'
Federal	64,931,000	61,510,000	72,840,000
State	6,164,000	6,611,000	10,433,000
Total deferred income tax provisions, net	71,095,000	68,121,000	83,273,000
Investment tax credits	-195,000	-195,000	-195,000
Total income tax expense	69,308,000	74,866,000	62,501,000
Reconciliation of federal statutory rate to effective tax rate	'	'	'
Book income before income taxes	184,625,000	178,567,000	162,211,000
Computed tax at federal statutory rate	64,619,000	62,499,000	56,774,000
Increases (reductions) resulting from:	'	'	'
Investment tax credits	-195,000	-195,000	-195,000
Allowance for equity funds used during construction	-3,784,000	-2,749,000	-3,689,000
Amortization of nuclear plant regulatory assets	6,867,000	9,334,000	8,885,000
State income taxes, net of federal income tax benefits	3,259,000	5,018,000	4,214,000
Other items, net	-1,458,000	959,000	-3,488,000
Total income tax expense	69,308,000	74,866,000	62,501,000
Effective income tax rates (in hundredths)	37.50%	41.90%	38.50%
Additional tax disclosure [Abstract]	'	'	'
Combined statutory federal and state income tax rates (in hundredths)	40.90%	40.90%	40.40%
Statutory rate of the Connecticut corporation business tax (in hundredths)	9.00%	8.25%	'
Effective book income tax rates (in hundredths)	37.50%	41.90%	38.50%
Changes gross income tax reserves [Roll Forward]	'	'	'
Beginning balance	0	13,676,000	'
Increases for tax positions related to current year	0	0	'
Reductions for tax positions of prior years	0	-13,676,000	'
Ending balance	0	0	13,676,000
Unrecognized tax benefits, interest on income taxes accrued	'	'	500,000
Unrecognized tax benefits that would impact the effective tax rate	0	0	'
Assets:	'	'	'
Deferred income taxes	21,742,000	41,605,000	'
Liabilities:	'	'	'
Deferred income taxes	540,542,000	462,940,000	'
Deferred income taxes - net	518,800,000	421,335,000	'
Deferred income tax assets:	'	'	'
Post-retirement benefits	90,300,000	151,203,000	'
Accrued removal obligation	119,904,000	105,329,000	'
Net operating loss carry forward	42,818,000	26,775,000	'
Other	104,467,000	58,266,000	'
Total deferred income tax assets	357,489,000	341,573,000	'
Deferred income tax liabilities:	'	'	'
Accelerated depreciation timing differences	364,321,000	317,885,000	'
Plant basis differences	243,629,000	178,989,000	'
Storm regulatory asset	5,883,000	21,102,000	'
Regulatory asset related to pension and other post-retirement benefits	110,980,000	171,576,000	'
Investment in GenConn	53,350,000	52,920,000	'
Other	98,126,000	20,436,000	'
Total deferred tax liabilities	876,289,000	762,908,000	'
Operating loss carryforwards balances [Abstract]	'	'	'
Federal net operating loss	122,339,000	76,500,000	'
Alternative minimum tax credit	2,697,000	2,488,000	'
State tax credits	$7,289,000	$3,104,000	'
Federal net operating loss, Year Expiration Begins	31-Dec-32	'	'
State tax credit, Year Expiration Begins	31-Dec-16	'	'

SUPPLEMENTARY_INFORMATION_Deta

SUPPLEMENTARY INFORMATION (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Depreciation and Amortization [Abstract]	'	'	'
Property, plant and equipment depreciation	$120,301	$112,002	$98,343
Amortization of nuclear plant regulatory assets	47,476	46,550	44,635
Amortization of other regulatory assets	22,050	22,745	24,436
Other	29	51	48
Total Amortization	69,555	69,346	69,119
Total depreciation and amortization	189,856	181,348	167,462
Taxes - Other than Income Taxes - Operating [Abstract]	'	'	'
Connecticut gross earnings	75,330	65,753	69,906
Local real estate and personal property	46,567	40,588	34,902
Payroll taxes	8,005	7,274	9,373
Other	556	422	30
Total Taxes - Other than Income Taxes	130,458	114,037	114,211
Other Income and (Deductions), net [Abstract]	'	'	'
Interest income	2,733	2,631	3,483
Allowance for funds used during construction - equity	10,811	7,480	10,539
Allowance for funds used during construction - debt	7,170	6,979	9,143
Weather insurance	-70	3,488	3,090
TSO incentives	0	2,745	0
Other	-11	1,923	677
Total Other Income and (Deductions), net	$20,633	$25,246	$26,932

PENSION_AND_OTHER_BENEFITS_Det

PENSION AND OTHER BENEFITS (Details) (USD $)	12 Months Ended
PENSION AND OTHER BENEFITS (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
PENSION AND OTHER BENEFITS [Abstract]	'		'		'
Potential funding requirement for 2014, minimum	$20,000,000		'		'
Potential funding requirement for 2014, maximum	25,000,000		'		'
Change in the discount rate assumed for pension expense (in hundredths)	0.25%		'		'
Effect of the change in the discount rate on pension expense	2,600,000		'		'
Change in the expected return on assets (in hundredths)	1.00%		'		'
Effect of the change in the expected return on assets on pension expenses	6,900,000		'		'
Change in the discount rate assumed, other postretirement plans (in hundredths)	0.25%		'		'
Effect of the change in the discount rate on other postretirement expense	300,000		'		'
Effect of the change in the discount rate on Projected Benefit Obligation	100,000,000		'		'
Change in the expected return on assets, other postretirement plans (in hundredths)	1.00%		'		'
Effect of the change in the expected return on assets on other postretirement expense	400,000		'		'
Target Allocations [Abstract]	'		'		'
Terms of other postretirement benefits plans - non union employees	'Non-union employees who are 55 years of age and whose sum of age and years of service at time of retirement is equal to or greater than 65 are eligible for benefits partially subsidized by UI. The amount of benefits subsidized by UI is determined by age and years of service at retirement. For funding purposes, UI established a 401(h) account in connection with the UI Pension Plan and Serial Voluntary Employee Benefit Association Trust (VEBA) accounts for the years 2007 through 2020 to fund other postretirement benefits for UI's non-union employees who retire on or after January 1, 1994. These VEBA accounts were approved by the IRS and UI contributed $4.5 million to fund the Serial VEBA accounts in 2007. UI does not expect to make a contribution in 2014 to fund OPEB for non-union employees.		'		'
Terms of other postretirement benefit plans - union employees	'Union employees whose sum of age and years of service at the time of retirement is equal to or greater than 85 (or who are 62 with at least 20 years of service) are eligible for benefits partially subsidized by UI. The amount of benefits subsidized by UI is determined by age and years of service at retirement. For funding purposes, UI established a VEBA to fund other postretirement benefits for UI's union employees. The funding strategy for the VEBA is to select funds that most clearly mirror the pension allocation strategy.		'		'
Description of alternative method to amortize prior service costs and unrecognized actuarial gains and losses.	'UIL Holdings utilizes an alternative method to amortize unrecognized actuarial gains and losses related to the pension and other postretirement benefits plans over the lesser of the average remaining service period or 10 years. For ASC 715 purposes, UIL Holdings does not recognize gains or losses until there is a variance in an amount equal to at least 5% of the greater of the projected benefit obligation or the market-related value of assets.		'		'
Change in Plan Assets [Roll Forward]	'		'		'
Fair value of plan assets at beginning of year	663,601,000		'		'
Fair value of plan assets at end of year	729,573,000		663,601,000		'
Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]	'		'		'
Aggregate service and interest cost components, increase	751,000		'		'
Aggregate service and interest cost components, decrease	-610,000		'		'
Accumulated post-retirement benefit obligation, increase	9,559,000		'		'
Accumulated post-retirement benefit obligation, decrease	-7,942,000		'		'
Defined Contribution Retirement Plans/401(k) Disclosure [Abstract]	'		'		'
Matching contributions	5,200,000		4,900,000		4,600,000
Pension Benefits [Member]	'		'		'
Change in Benefit Obligation [Roll Forward]	'		'		'
Benefit obligation at beginning of year	950,608,000		792,101,000		'
Net transfer in due to acquisition of the Gas Companies	0		0		'
Service cost	14,783,000		12,032,000		12,574,000
Interest cost	39,948,000		41,470,000		40,484,000
Participant contributions	0		0		'
Settlements	-2,367,000	[1]	0	[1]	'
Actuarial (gain) loss	96,739,000		149,088,000		'
Benefits paid (including expenses)	-46,971,000		-44,083,000		'
Benefit obligation at end of year	859,262,000		950,608,000		792,101,000
Change in Plan Assets [Roll Forward]	'		'		'
Fair value of plan assets at beginning of year	625,061,000		548,122,000		'
Net transfer in due to acquisitions of Gas Companies	0		0		'
Actual return on plan assets	54,259,000		71,595,000		'
Employer contributions	58,428,000		49,427,000		'
Participant contributions	0		0		'
Settlements	-2,367,000	[1]	0	[1]	'
Benefits paid (including expenses)	-46,971,000		-44,083,000		'
Fair value of plan assets at end of year	688,410,000		625,061,000		548,122,000
Funded Status [Abstract]	'		'		'
Projected benefits (less than) greater than plan assets	170,852,000		325,547,000		'
Amounts Recognized in the Statement of Financial Position consist of [Abstract]	'		'		'
Non-current assets	0		0		'
Current liabilities	0		0		'
Non-current liabilities	170,852,000		325,547,000		'
Amounts Recognized as a Regulatory Asset consist of: [Abstract]	'		'		'
Transition obligation (asset)	0		0		'
Prior service cost	365,000		859,000		'
Net (gain) loss	123,178,000		244,032,000		'
Total recognized as regulatory assets	123,543,000		244,891,000		'
Pension Plans with Accumulated Benefit Obligations in excess of Plan Assets [Abstract]	'		'		'
Projected benefit obligation	859,262,000		950,608,000		'
Accumulated benefit obligation	784,081,000		858,803,000		'
Fair value of plan assets	688,410,000		625,061,000		'
Components of net periodic benefit cost:	'		'		'
Service cost	14,783,000		12,032,000		12,574,000
Interest cost	39,948,000		41,470,000		40,484,000
Expected return on plan assets	-51,453,000		-44,874,000		-42,588,000
Amortization of:	'		'		'
Prior service costs	605,000		647,000		643,000
Transition obligation (asset)	0		0		0
Actuarial (gain) loss	20,829,000		13,173,000		14,032,000
Settlements	632,000	[1]	0	[1]	0	[1]
Net periodic benefit cost	25,344,000		22,448,000		25,145,000
Estimated Future Benefit Payments [Abstract]	'		'		'
2014	45,266,000		'		'
2015	49,699,000		'		'
2016	49,437,000		'		'
2017	51,358,000		'		'
2018	54,013,000		'		'
2019-2022	288,030,000		'		'
Pension Benefits [Member] \| Minimum [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Average wage increase (in hundredths)	3.50%		3.50%		'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'		'		'
Discount rate (in hundredths)	4.00%		5.05%		5.10%
Average wage increase (in hundredths)	3.50%		3.50%		3.50%
Return on plan assets (in hundredths)	7.75%		7.75%		8.25%
Pension Benefits [Member] \| Maximum [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Average wage increase (in hundredths)	3.80%		3.80%		'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'		'		'
Discount rate (in hundredths)	4.25%		5.30%		5.35%
Average wage increase (in hundredths)	3.80%		3.80%		3.80%
Return on plan assets (in hundredths)	8.00%		8.00%		8.50%
Pension Benefits [Member] \| Non Qualified Plans [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	4.90%		4.00%		'
Pension Benefits [Member] \| Qualified Plans [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	5.20%		4.25%		'
Pension Benefits [Member] \| Other Changes in Plans Assets and Benefit Obligations Recognized as a Regulatory Assets [Member]	'		'		'
Components of net periodic benefit cost:	'		'		'
Net (gain) loss	-99,572,000		122,368,000		34,524,000
Amortization of:	'		'		'
Current year prior service costs	111,000		0		0
Prior service costs	-605,000		-647,000		-626,000
Transition obligation (asset)	0		0		0
Actuarial (gain) loss	-20,829,000		-13,173,000		-14,032,000
Settlements	-632,000	[1]	0	[1]	0	[1]
Total recognized as regulatory asset	-121,527,000		108,548,000		19,866,000
Total recognized in net periodic benefit costs and regulatory asset	-96,183,000		130,996,000		45,011,000
Pension Benefits [Member] \| Estimated amortization from Regulatory Assets [Member]	'		'		'
Amortization of:	'		'		'
Prior service costs	291,000		605,000		647,000
Transition obligation (asset)	0		0		0
Amortization of net (gain) loss	12,386,000		20,808,000		13,173,000
Total estimated amortizations	12,677,000		21,413,000		13,820,000
Other Post-Retirement Benefits [Member]	'		'		'
Change in Benefit Obligation [Roll Forward]	'		'		'
Benefit obligation at beginning of year	136,687,000		122,382,000		'
Net transfer in due to acquisition of the Gas Companies	0		0		'
Service cost	1,923,000		1,604,000		2,164,000
Interest cost	5,539,000		6,246,000		6,634,000
Participant contributions	1,253,000		1,305,000		'
Settlements	0	[1]	0	[1]	'
Actuarial (gain) loss	13,893,000		12,500,000		'
Benefits paid (including expenses)	-11,807,000		-7,350,000		'
Benefit obligation at end of year	119,702,000		136,687,000		122,382,000
Change in Plan Assets [Roll Forward]	'		'		'
Fair value of plan assets at beginning of year	38,540,000		37,573,000		'
Net transfer in due to acquisitions of Gas Companies	0		0		'
Actual return on plan assets	6,003,000		4,092,000		'
Employer contributions	0		0		'
Participant contributions	1,253,000		1,305,000		'
Settlements	0	[1]	0	[1]	'
Benefits paid (including expenses)	-4,633,000		-4,430,000		'
Fair value of plan assets at end of year	41,163,000		38,540,000		37,573,000
Funded Status [Abstract]	'		'		'
Projected benefits (less than) greater than plan assets	78,539,000		98,147,000		'
Amounts Recognized in the Statement of Financial Position consist of [Abstract]	'		'		'
Non-current assets	0		0		'
Current liabilities	0		0		'
Non-current liabilities	78,539,000		98,147,000		'
Amounts Recognized as a Regulatory Asset consist of: [Abstract]	'		'		'
Transition obligation (asset)	0		0		'
Prior service cost	1,447,000		45,000		'
Net (gain) loss	-792,000		19,643,000		'
Total recognized as regulatory assets	655,000		19,688,000		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	5.20%		4.25%		'
Health care trend rate (current year) (in hundredths)	7.00%		7.50%		'
Health care trend rate (2019-2028 forward)	5.00%		5.00%		'
Components of net periodic benefit cost:	'		'		'
Service cost	1,923,000		1,604,000		2,164,000
Interest cost	5,539,000		6,246,000		6,634,000
Expected return on plan assets	-2,590,000		-2,503,000		-2,965,000
Amortization of:	'		'		'
Prior service costs	-50,000		-69,000		-101,000
Transition obligation (asset)	0		392,000		1,020,000
Actuarial (gain) loss	1,776,000		965,000		2,008,000
Settlements	0	[1]	0	[1]	0	[1]
Net periodic benefit cost	6,598,000		6,635,000		8,760,000
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'		'		'
Composite health care trend rate (current year), (in hundredths)	7.50%		8.00%		'
Composite health care trend rate (2019 forward), (in hundredths)	5.00%		5.00%		'
Estimated Future Benefit Payments [Abstract]	'		'		'
2014	7,447,000		'		'
2015	7,710,000		'		'
2016	7,763,000		'		'
2017	7,892,000		'		'
2018	7,969,000		'		'
2019-2022	40,009,000		'		'
Other Post-Retirement Benefits [Member] \| Minimum [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	4.85%		4.00%		'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'		'		'
Discount rate (in hundredths)	4.00%		5.05%		5.15%
Return on plan assets (in hundredths)	5.56%		5.56%		5.86%
Composite health care trend rate (current year), (in hundredths)	'		7.80%		'
Composite health care trend rate (2019 forward), (in hundredths)	'		'		4.50%
Other Post-Retirement Benefits [Member] \| Maximum [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	5.20%		4.25%		'
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]	'		'		'
Discount rate (in hundredths)	4.25%		5.30%		5.30%
Return on plan assets (in hundredths)	8.00%		8.00%		8.25%
Composite health care trend rate (current year), (in hundredths)	'		8.50%		'
Composite health care trend rate (2019 forward), (in hundredths)	'		'		5.00%
Other Post-Retirement Benefits [Member] \| Other Changes in Plans Assets and Benefit Obligations Recognized as a Regulatory Assets [Member]	'		'		'
Components of net periodic benefit cost:	'		'		'
Net (gain) loss	-17,257,000		10,760,000		-6,608,000
Amortization of:	'		'		'
Current year prior service costs	1,352,000		0		0
Prior service costs	50,000		69,000		101,000
Transition obligation (asset)	0		-392,000		-1,020,000
Actuarial (gain) loss	-1,776,000		-965,000		-2,008,000
Settlements	0	[1]	0	[1]	0	[1]
Total recognized as regulatory asset	-17,631,000		9,472,000		-9,535,000
Total recognized in net periodic benefit costs and regulatory asset	-11,033,000		16,107,000		-775,000
Other Post-Retirement Benefits [Member] \| Estimated amortization from Regulatory Assets [Member]	'		'		'
Amortization of:	'		'		'
Prior service costs	284,000		-50,000		-69,000
Transition obligation (asset)	0		0		392,000
Amortization of net (gain) loss	-298,000		1,939,000		965,000
Total estimated amortizations	-14,000		1,889,000		1,288,000
Other Post-Retirement Benefits [Member] \| Gas Companies Employees [Member]	'		'		'
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]	'		'		'
Discount rate (in hundredths)	4.85%		4.00%		'
UI [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Account contributions to fund Serial VEBA Accounts in 2007	4,500,000		'		'
Percentage of employees represented by Local 470-1 Utility Workers Union of America (in hundredths)	55.00%		'		'
Regulatory assets of pension and other postretirement plans	$124,200,000		$264,600,000		'
Equity Securities [Member]	'		'		'
Target Allocations [Abstract]	'		'		'
Target allocation of equity securities for 2013 (in hundredths)	50.00%		'		'
Debt Securities [Member]	'		'		'
Target Allocations [Abstract]	'		'		'
Target allocation of equity securities for 2013 (in hundredths)	40.00%		'		'
Other Securities [Member]	'		'		'
Target Allocations [Abstract]	'		'		'
Target allocation of equity securities for 2013 (in hundredths)	10.00%		'		'

[1]	Reflects settlement charges resulting from a distribution to a former employee upon retirement.

RELATED_PARTY_TRANSACTIONS_Det

RELATED PARTY TRANSACTIONS (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
RELATED PARTY TRANSACTIONS [Abstract]	'	'	'
Lease payments for office space	$1.50	$4.80	$11.40
GenConn [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Interest income related to the promissory note	'	'	$1.20

LEASE_OBLIGATIONS_Details

LEASE OBLIGATIONS (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum lease payments under non-cancelable operating leases [Abstract]	'	'	'
2014	$4,504	'	'
2015	3,576	'	'
2016	3,606	'	'
2017	3,691	'	'
2018	3,537	'	'
2019-after	39,820	'	'
Total	58,734	'	'
Rental payments included in operating expenses [Abstract]	'	'	'
Rental payments	5,886	11,639	17,676
Less: Sublease rental payments received	0	241	1,148
Rental payments charged to operating expenses	$5,886	$11,398	$16,528

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
	Subcontractor
Connecticut Yankee Atomic Power Company [Member]	'
Site Decontamination, Demolition and Remediation Costs [Line Items]	'
Percentage stock ownership share in CT Yankee atomic power company (in hundredths)	9.50%
Carrying value of stock in CT Yankee atomic power company	$0.10
Damages awarded for spent fuel related costs	39.7
Entity's share of amount awarded to CT Yankee atomic power company	3.8
Second set of damage claims relating to failure to remove spent atomic fuel	135
Actual second set of damages award	126.3
Entity's share of second set of damage claims	12
Mill River New Haven Connecticut Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Line Items]	'
Amount placed in escrow for estimated remediation	1.9
Remaining amount of escrow	0.1
New Haven Harbor Station Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Line Items]	'
Site contingency, liability accrued	3.2
Mill Street Greenfield Massachusetts Site [Member]	'
Site Decontamination, Demolition and Remediation Costs [Line Items]	'
Site contingency, liability accrued	1.2
East Street Site Pittsfield Massachusetts [Member]	'
Site Decontamination, Demolition and Remediation Costs [Line Items]	'
Site contingency, liability accrued	2.9
Middletown/Norwalk Transmission Projects [Member]	'
Middletown/Norwalk Transmission Project [Abstract]	'
Amount sought for change order requests	33.3
Percentage of general contractor mark-up on approved subcontractor change order claims (in hundredths)	10.00%
Amount of general contractor mark up on approved subcontractor change order claims	2.3
Subcontractors responsible for civil construction	2
Revised estimate for change order requests	7.7
Amount in Memorandum of Decision issued by the court for the company to pay to contractor	$1.30

FAIR_VALUE_MEASUREMENTS_Detail

FAIR VALUE MEASUREMENTS (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Liabilities:	'	'
Long-term debt	$1,704,095	$1,610,550
Fair Value, Measurements, Recurring [Member]	'	'
Assets:	'	'
Derivative assets	53,447	78,838
Noncurrent investments available for sale	11,148	9,902
Deferred Compensation Plan	3,775	3,745
Supplemental retirement benefit trust life insurance policies	7,898	6,438
Total financial assets, fair value	76,268	98,923
Liabilities:	'	'
Derivative liabilities	196,233	255,443
Long-term debt	1,846,867	1,886,440
Total financial liabilities, fair value	2,043,100	2,141,883
Net fair value assets/(liabilities)	-1,966,832	-2,042,960
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Assets:	'	'
Derivative assets	0	0
Noncurrent investments available for sale	11,148	9,902
Deferred Compensation Plan	3,775	3,745
Supplemental retirement benefit trust life insurance policies	0	0
Total financial assets, fair value	14,923	13,647
Liabilities:	'	'
Derivative liabilities	0	0
Long-term debt	0	0
Total financial liabilities, fair value	0	0
Net fair value assets/(liabilities)	14,923	13,647
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'
Assets:	'	'
Derivative assets	0	0
Noncurrent investments available for sale	0	0
Deferred Compensation Plan	0	0
Supplemental retirement benefit trust life insurance policies	7,898	6,438
Total financial assets, fair value	7,898	6,438
Liabilities:	'	'
Derivative liabilities	0	0
Long-term debt	1,846,867	1,886,440
Total financial liabilities, fair value	1,846,867	1,886,440
Net fair value assets/(liabilities)	-1,838,969	-1,880,002
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'
Assets:	'	'
Derivative assets	53,447	78,838
Noncurrent investments available for sale	0	0
Deferred Compensation Plan	0	0
Supplemental retirement benefit trust life insurance policies	0	0
Total financial assets, fair value	53,447	78,838
Liabilities:	'	'
Derivative liabilities	196,233	255,443
Long-term debt	0	0
Total financial liabilities, fair value	196,233	255,443
Net fair value assets/(liabilities)	($142,786)	($176,605)

FAIR_VALUE_MEASUREMENTS_Unobse

FAIR VALUE MEASUREMENTS, Unobservable Input Reconciliation (Details) (Contract For Difference [Member], USD $)	Dec. 31, 2013
Contract For Difference [Member]	'
Unobservable input [Abstract]	'
Risk of non-performance, lower range (in hundredths)	0.00%
Risk of non-performance, upper range (in hundredths)	0.62%
Discount rate, lower range (in hundredths)	1.75%
Discount rate, upper range (in hundredths)	3.21%
Forward pricing, lower range (in dollars per MW)	$1.40
Forward pricing, upper range (in dollars per MW)	$9.83

FAIR_VALUE_MEASUREMENTS_Assets

FAIR VALUE MEASUREMENTS, Assets and Liabilities Classified as Level 3 (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Changes in fair value of assets and liabilities classified as level 3 [Roll Forward]	'	'
Net fair value assets/(liabilities), Beginning balance	($176,605)	($180,581)
Unrealized gains and (losses), net [Abstract]	'	'
Included in earnings	0	3,488
Included in regulatory assets/(liabilities)	33,819	7,488
Settlements	0	-7,000
Net fair value assets/(liabilities), Ending balance	-142,786	-176,605
Change in unrealized gains (losses) net relating to net derivative assets/(liabilities), still held as of December 31, 2012	$33,819	$7,488

FAIR_VALUE_MEASUREMENTS_Regula

FAIR VALUE MEASUREMENTS, Regulatory Assets and Liabilities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Change in regulatory asset/liability balances [Roll Forward]	'	'
Net regulatory assets/(liabilities)	$176,605	$184,093
Unrealized (gains) and losses, net	-33,819	-7,488
Net regulatory assets/(liabilities)	$142,786	$176,605

FAIR_VALUE_MEASUREMENTS_Define

FAIR VALUE MEASUREMENTS, Defined Benefit Pension Plan (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	$729,573	$663,601	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	41,163	40,146	'
Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	653,579	595,772	'
Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	34,831	27,683	'
Pension [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	688,410	625,061	548,122
Pension [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	1,606	'
Pension [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	653,579	595,772	'
Pension [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	34,831	27,683	'
Pension [Member] \| Mutual Funds [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	653,579	595,772	'
Pension [Member] \| Mutual Funds [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Pension [Member] \| Mutual Funds [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	653,579	595,772	'
Pension [Member] \| Mutual Funds [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Pension [Member] \| Hedge Funds [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	34,831	27,683	'
Pension [Member] \| Hedge Funds [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Pension [Member] \| Hedge Funds [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Pension [Member] \| Hedge Funds [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	34,831	27,683	'
Pension [Member] \| Cash and Cash Equivalents [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	1,606	'
Pension [Member] \| Cash and Cash Equivalents [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	1,606	'
Pension [Member] \| Cash and Cash Equivalents [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
Pension [Member] \| Cash and Cash Equivalents [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
OPEB [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	41,163	38,540	'
OPEB [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	41,163	38,540	'
OPEB [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
OPEB [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
OPEB [Member] \| Mutual Funds [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	41,163	38,540	'
OPEB [Member] \| Mutual Funds [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	41,163	38,540	'
OPEB [Member] \| Mutual Funds [Member] \| Significant Other Observable Inputs (Level 2) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	0	0	'
OPEB [Member] \| Mutual Funds [Member] \| Significant Unobservable Inputs (Level 3) [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Fair value of plan assets	$0	$0	'

FAIR_VALUE_MEASUREMENTS_Pensio

FAIR VALUE MEASUREMENTS, Pension assets, level 3 fair value (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]	'	'
Fair value of plan assets, beginning of period	$27,683	$0
Unrealized/Realized gains and (losses), net	2,035	479
Purchases	5,113	27,204
Fair value of plan assets, end of period	$34,831	$27,683

QUARTERLY_FINANCIAL_DATA_UNAUD2

QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]	'		'		'		'		'		'		'		'		'	'	'
Operating Revenues	$435,125		$316,478		$319,074		$548,039		$422,953		$322,888		$282,842		$457,818		$1,618,716	$1,486,501	$1,570,094
Operating Income	78,362		22,659		43,235		96,233		67,496		39,126		36,507		87,461		240,489	230,590	219,382
Net income	40,419		5,157		17,934		51,807		28,838		15,775		12,012		47,076		115,317	103,701	99,710
Net income attributable to UIL Holdings	$40,406		$5,144		$17,924		$51,791		$28,839		$15,749		$11,999		$47,050		$115,265	$103,637	$99,656
Earnings Per Share of Common Stock - Basic: (in dollars per share)	$0.71	[1]	$0.10	[1]	$0.35	[1]	$1.02	[1]	$0.57	[1]	$0.31	[1]	$0.24	[1]	$0.93	[1]	$2.20	$2.04	$1.96
Earnings Per Share of Common Stock - Diluted: (in dollars per share)	$0.71	[1]	$0.10	[1]	$0.35	[1]	$1.01	[1]	$0.56	[1]	$0.31	[1]	$0.23	[1]	$0.92	[1]	$2.18	$2.02	$1.95

[1]	Based on weighted average number of shares outstanding each quarter. Diluted earnings per share reflects the effect of dilutive stock options, performance shares and restricted stock. Quarterly per share amounts are not intended to be additive.

SEGMENT_INFORMATION_Details

SEGMENT INFORMATION (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Segment Reporting Information [Line Items]

Operating Revenues

$435,125,000

$316,478,000

$319,074,000

$548,039,000

$422,953,000

$322,888,000

$282,842,000

$457,818,000

$1,618,716,000

$1,486,501,000

$1,570,094,000

Purchased power and gas

577,324,000

524,780,000

609,228,000

Operation and maintenance

384,029,000

356,277,000

381,814,000

Transmission wholesale

88,206,000

79,469,000

77,997,000

Depreciation and amortization

189,856,000

181,348,000

167,462,000

Taxes - other than income taxes

130,458,000

114,037,000

114,211,000

Regulatory disallowances

8,354,000

Operating Income

78,362,000

22,659,000

43,235,000

96,233,000

67,496,000

39,126,000

36,507,000

87,461,000

240,489,000

230,590,000

219,382,000

Other Income and (Deductions), net

20,633,000

25,246,000

26,932,000

Interest Charges, net

91,769,000

92,542,000

95,385,000

Income from Equity Investments

15,272,000

15,273,000

11,282,000

Income (Loss) Before Income Taxes

184,625,000

178,567,000

162,211,000

Income Taxes

69,308,000

74,866,000

62,501,000

Net Income (Loss)

40,419,000

5,157,000

17,934,000

51,807,000

28,838,000

15,775,000

12,012,000

47,076,000

115,317,000

103,701,000

99,710,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

52,000

64,000

54,000

Net Income attributable to UIL Holdings

40,406,000

5,144,000

17,924,000

51,791,000

28,839,000

15,749,000

11,999,000

47,050,000

115,265,000

103,637,000

99,656,000

Total Capital Expenditure

305,178,000

[1]

288,633,000

[1]

328,079,000

[1]

Total Assets

5,144,220,000

5,019,164,000

[2]

5,144,220,000

5,019,164,000

[2]

4,744,609,000

[2]

Net plant in service segregated by segment [Abstract]

Goodwill

266,205,000

Electric Distribution Reportable Segment [Member]

Segment Reporting Information [Line Items]

Operating Revenues

560,877,000

561,148,000

599,153,000

Purchased power and gas

139,135,000

154,546,000

180,149,000

Operation and maintenance

189,378,000

178,862,000

216,361,000

Transmission wholesale

Depreciation and amortization

91,670,000

88,672,000

83,725,000

Taxes - other than income taxes

49,421,000

44,845,000

45,967,000

Regulatory disallowances

8,354,000

Operating Income

82,919,000

94,223,000

72,951,000

Other Income and (Deductions), net

13,335,000

16,562,000

14,697,000

Interest Charges, net

27,052,000

28,308,000

30,489,000

Income from Equity Investments

15,272,000

15,273,000

11,282,000

Income (Loss) Before Income Taxes

84,474,000

97,750,000

68,441,000

Income Taxes

37,816,000

45,091,000

30,865,000

Net Income (Loss)

46,658,000

52,659,000

37,576,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

Net Income attributable to UIL Holdings

46,658,000

52,659,000

37,576,000

Total Capital Expenditure

[1]

Total Assets

[3]

[4]

[3]

[4]

Electric Transmission Reportable Segment [Member]

Segment Reporting Information [Line Items]

Operating Revenues

242,681,000

222,314,000

198,503,000

Purchased power and gas

Operation and maintenance

45,540,000

43,185,000

32,027,000

Transmission wholesale

88,206,000

79,469,000

77,997,000

Depreciation and amortization

16,353,000

14,890,000

12,690,000

Taxes - other than income taxes

33,991,000

26,773,000

24,736,000

Regulatory disallowances

Operating Income

58,591,000

57,997,000

51,053,000

Other Income and (Deductions), net

4,874,000

3,945,000

6,651,000

Interest Charges, net

12,046,000

12,941,000

13,235,000

Income from Equity Investments

Income (Loss) Before Income Taxes

51,419,000

49,001,000

44,469,000

Income Taxes

17,784,000

17,025,000

13,186,000

Net Income (Loss)

33,635,000

31,976,000

31,283,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

Net Income attributable to UIL Holdings

33,635,000

31,976,000

31,283,000

Total Capital Expenditure

[1]

Total Assets

[3]

[4]

[3]

[4]

Total Electric Reportable Segments [Member]

Segment Reporting Information [Line Items]

Operating Revenues

803,558,000

783,462,000

797,656,000

Purchased power and gas

139,135,000

154,546,000

180,149,000

Operation and maintenance

234,918,000

222,047,000

248,388,000

Transmission wholesale

88,206,000

79,469,000

77,997,000

Depreciation and amortization

108,023,000

103,562,000

96,415,000

Taxes - other than income taxes

83,412,000

71,618,000

70,703,000

Regulatory disallowances

8,354,000

Operating Income

141,510,000

152,220,000

124,004,000

Other Income and (Deductions), net

18,209,000

20,507,000

21,348,000

Interest Charges, net

39,098,000

41,249,000

43,724,000

Income from Equity Investments

15,272,000

15,273,000

11,282,000

Income (Loss) Before Income Taxes

135,893,000

146,751,000

112,910,000

Income Taxes

55,600,000

62,116,000

44,051,000

Net Income (Loss)

80,293,000

84,635,000

68,859,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

Net Income attributable to UIL Holdings

80,293,000

84,635,000

68,859,000

Total Capital Expenditure

160,042,000

[1]

178,107,000

[1]

247,563,000

[1]

Total Assets

2,950,707,000

[3]

2,935,562,000

[4]

2,950,707,000

[3]

2,935,562,000

[4]

2,716,460,000

[4]

Gas Distribution Reportable Segment [Member]

Segment Reporting Information [Line Items]

Operating Revenues

815,023,000

702,887,000

772,315,000

Purchased power and gas

438,189,000

370,234,000

429,079,000

Operation and maintenance

154,418,000

137,707,000

133,126,000

Transmission wholesale

Depreciation and amortization

77,890,000

75,205,000

70,694,000

Taxes - other than income taxes

46,477,000

42,254,000

43,494,000

Regulatory disallowances

Operating Income

98,049,000

77,487,000

95,922,000

Other Income and (Deductions), net

-323,000

4,071,000

6,571,000

Interest Charges, net

28,935,000

28,001,000

28,939,000

Income from Equity Investments

Income (Loss) Before Income Taxes

68,791,000

53,557,000

73,554,000

Income Taxes

23,309,000

21,305,000

29,721,000

Net Income (Loss)

45,482,000

32,252,000

43,833,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

52,000

64,000

54,000

Net Income attributable to UIL Holdings

45,430,000

32,188,000

43,779,000

Total Capital Expenditure

97,346,000

[1]

80,837,000

[1]

60,349,000

[1]

Total Assets

2,010,246,000

[5]

1,993,560,000

[2]

2,010,246,000

[5]

1,993,560,000

[2]

1,953,079,000

[2]

Net plant in service segregated by segment [Abstract]

Goodwill

266,200,000

266,800,000

266,200,000

266,800,000

Other [Member]

Segment Reporting Information [Line Items]

Operating Revenues

135,000

152,000

123,000

Purchased power and gas

Operation and maintenance

-5,307,000

-3,477,000

300,000

Transmission wholesale

Depreciation and amortization

3,943,000

2,581,000

353,000

Taxes - other than income taxes

569,000

165,000

14,000

Regulatory disallowances

Operating Income

930,000

883,000

-544,000

Other Income and (Deductions), net

2,747,000

668,000

-987,000

Interest Charges, net

23,736,000

23,292,000

22,722,000

Income from Equity Investments

Income (Loss) Before Income Taxes

-20,059,000

-21,741,000

-24,253,000

Income Taxes

-9,601,000

-8,555,000

-11,271,000

Net Income (Loss)

-10,458,000

-13,186,000

-12,982,000

Less: Preferred Stock Dividends of Subsidiary, Noncontrolling Interests

Net Income attributable to UIL Holdings

-10,458,000

-13,186,000

-12,982,000

Total Capital Expenditure

47,790,000

[1]

29,689,000

[1]

20,167,000

[1]

Total Assets

183,267,000

90,042,000

183,267,000

90,042,000

75,070,000

Distribution Segment [Member]

Net plant in service segregated by segment [Abstract]

Net plant in service

1,181,100,000

1,114,200,000

1,181,100,000

1,114,200,000

1,029,800,000

Transmission Segment [Member]

Net plant in service segregated by segment [Abstract]

Net plant in service

$656,000,000

$612,000,000

$656,000,000

$612,000,000

$495,800,000

[1]

Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.

[2]

Includes $266.8 million of goodwill in the Gas Distribution segment as of December 31, 2012 and 2011.

[3]

Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2013, was $1,181.1 million and $656.0 million for Distribution and Transmission, respectively.

[4]

Information for segmenting total assets between Distribution and Transmission is not available. Total Electric Distribution and Transmission assets are disclosed in the Total Electric and Distribution and Transmission column. Net plant in service is segregated by segment and, as of December 31, 2012, was $1,114.2 million and $612.0 million for Distribution and Transmission, respectively. As of December 31, 2011, net plant in service was $1,029.8 million and $495.8 million for Distribution and Transmission, respectively.

[5]

Includes $266.2 million of goodwill in the Gas Distribution segment as of December 31, 2013.

Schedule_I_Condensed_Financial1

Schedule I - Condensed Financial Statements of Registrant, Statements of Income (Details) (USD $)

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Operating Expenses

Operation and maintenance

$384,029

$356,277

$381,814

Depreciation and amortization

189,856

181,348

167,462

Taxes - other than income taxes

130,458

114,037

114,211

Total Operating Expenses

1,378,227

1,255,911

1,350,712

Operating Income

78,362

22,659

43,235

96,233

67,496

39,126

36,507

87,461

240,489

230,590

219,382

Other Income and (Deductions), net

20,633

25,246

26,932

Interest Charges, net

91,769

92,542

95,385

Income Taxes

69,308

74,866

62,501

Net Income

40,419

5,157

17,934

51,807

28,838

15,775

12,012

47,076

115,317

103,701

99,710

Net Income attributable to UIL Holdings

40,406

5,144

17,924

51,791

28,839

15,749

11,999

47,050

115,265

103,637

99,656

Average Number of Common Shares Outstanding - Basic (in shares)

52,415,000

50,831,000

50,609,000

Average Number of Common Shares Outstanding - Diluted (in shares)

52,711,000

51,108,000

50,926,000

Earnings Per Share of Common Stock - Basic: (in dollars per share)

$0.71

[1]

$0.10

[1]

$0.35

[1]

$1.02

[1]

$0.57

[1]

$0.31

[1]

$0.24

[1]

$0.93

[1]

$2.20

$2.04

$1.96

Earnings Per Share of Common Stock - Diluted: (in dollars per share)

$0.71

[1]

$0.10

[1]

$0.35

[1]

$1.01

[1]

$0.56

[1]

$0.31

[1]

$0.23

[1]

$0.92

[1]

$2.18

$2.02

$1.95

UIL Holdings Corporation [Member]

Condensed Financial Statements, Captions [Line Items]

Operating Revenues

6,209

4,193

353

Operating Expenses

Operation and maintenance

844

639

548

Depreciation and amortization

3,842

2,530

306

Taxes - other than income taxes

562

156

Total Operating Expenses

5,248

3,325

864

Operating Income

961

868

-511

Other Income and (Deductions), net

2,552

351

-1,609

Interest Charges, net

23,735

23,292

22,784

Equity in Earnings of Subsidiaries

125,871

117,083

113,081

Income Before Income Taxes

105,649

95,010

88,177

Income Taxes

-9,668

-8,691

-11,533

Net Income

115,317

103,701

99,710

Net Income Attributable to Noncontrolling Interest

Net Income attributable to UIL Holdings

$115,265

$103,637

$99,656

Average Number of Common Shares Outstanding - Basic (in shares)

52,415

50,831

50,609

Average Number of Common Shares Outstanding - Diluted (in shares)

52,711

51,108

50,926

Earnings Per Share of Common Stock - Basic: (in dollars per share)

$2.20

$2.04

$1.96

Earnings Per Share of Common Stock - Diluted: (in dollars per share)

$2.18

$2.02

$1.95

[1]

Schedule_I_Condensed_Financial2

Schedule I - Condensed Financial Statements of Registrant, Statements of Comprehensive Income (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net Income	$40,419	$5,157	$17,934	$51,807	$28,838	$15,775	$12,012	$47,076	$115,317	$103,701	$99,710
Changes in unrealized gains (losses) related to pension and other post-retirement benefit plans	'	'	'	'	'	'	'	'	1,008	-90	-576
Other	'	'	'	'	'	'	'	'	-24	16	35
Total other comprehensive income (loss), net of deferred income taxes	'	'	'	'	'	'	'	'	984	-74	-541
Less:	'	'	'	'	'	'	'	'	'	'	'
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	'	'	'	'	'	'	'	'	52	64	54
Comprehensive Income attributable to UIL Holdings	'	'	'	'	'	'	'	'	116,249	103,563	99,115
UIL Holdings Corporation [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net Income	'	'	'	'	'	'	'	'	115,317	103,701	99,710
Changes in unrealized gains (losses) related to pension and other post-retirement benefit plans	'	'	'	'	'	'	'	'	1,008	-90	-576
Other	'	'	'	'	'	'	'	'	-24	16	35
Total other comprehensive income (loss), net of deferred income taxes	'	'	'	'	'	'	'	'	984	-74	-541
Comprehensive Income	'	'	'	'	'	'	'	'	116,301	103,627	99,169
Less:	'	'	'	'	'	'	'	'	'	'	'
Preferred Stock Dividends of Subsidiary, Noncontrolling Interests	'	'	'	'	'	'	'	'	52	64	54
Comprehensive Income attributable to UIL Holdings	'	'	'	'	'	'	'	'	$116,249	$103,563	$99,115

Schedule_I_Condensed_Financial3

Schedule I - Condensed Financial Statements of Registrant, Balance Sheet (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Current Assets	'	'		'		'
Unrestricted cash and temporary cash investments	$69,153	$17,857		$30,999		$90,281
Intercompany receivable	245,252	238,986		'		'
Deferred income taxes	21,742	41,605		'		'
Refundable taxes	8,244	1,686		'		'
Other	12,122	11,507		'		'
Total Current Assets	888,004	628,683		'		'
Investments in Subsidiaries	118,241	124,799		'		'
Net Property, Plant and Equipment	3,068,680	2,847,151		'		'
Other Assets	11,640	28,587		'		'
Total Assets	5,144,220	5,019,164	[1]	4,744,609	[1]	'
Current Liabilities	'	'		'		'
Line of credit borrowings	0	187,000		'		'
Accounts payable	164,416	189,991		'		'
Dividends payable	24,392	21,887		'		'
Total Current Liabilities	612,823	625,056		'		'
Deferred income taxes	540,542	462,940		'		'
Other Liabilities	49,047	49,506		'		'
CAPITALIZATION	'	'		'		'
Long-term debt, net of unamortized discount and premium	1,723,842	1,600,354		'		'
Net Common Stock Equity	1,353,815	1,116,553		1,094,361		1,076,142
Total Capitalization	3,077,997	2,717,247		'		'
Total Liabilities and Capitalization	5,144,220	5,019,164		'		'
UIL Holdings Corporation [Member]	'	'		'		'
Current Assets	'	'		'		'
Unrestricted cash and temporary cash investments	28,915	115		2,664		10,532
Intercompany receivable	22,934	3,264		'		'
Deferred income taxes	19,927	2,145		'		'
Refundable taxes	13,337	24,101		'		'
Other	5,720	4,553		'		'
Total Current Assets	90,833	34,178		'		'
Investments in Subsidiaries	1,668,558	1,689,917		'		'
Net Property, Plant and Equipment	105,078	60,588		'		'
Other Assets	6,520	6,095		'		'
Total Assets	1,870,989	1,790,778		'		'
Current Liabilities	'	'		'		'
Line of credit borrowings	0	157,000		'		'
Accounts payable	15,780	22,242		'		'
Dividends payable	24,392	21,887		'		'
Other	23,500	21,079		'		'
Total Current Liabilities	63,672	222,208		'		'
Deferred income taxes	1,035	0		'		'
Other Liabilities	5,558	4,934		'		'
CAPITALIZATION	'	'		'		'
Long-term debt, net of unamortized discount and premium	447,403	447,083		'		'
Net Common Stock Equity	1,353,321	1,116,553		'		'
Total Capitalization	1,800,724	1,563,636		'		'
Total Liabilities and Capitalization	$1,870,989	$1,790,778		'		'

[1]	Includes $266.8 million of goodwill in the Gas Distribution segment as of December 31, 2012 and 2011.

Schedule_I_Condensed_Financial4

Schedule I - Condensed Financial Statements of Registrant, Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'		'		'
Net Cash provided by Operating Activities	$325,208		$333,941		$222,862
Cash Flows from Investing Activities	'		'		'
Acquisition of Gas Companies	0		0		11,211
Plant expenditures	-305,178	[1]	-288,633	[1]	-328,079	[1]
Intercompany loan receivable	0		0		-1,050
Other	360		844		401
Net Cash (used in) Investing Activities	-299,201		-306,259		-326,033
Cash Flows from Financing Activities	'		'		'
Issuance of common stock	206,516		1,943		200
Payments on long-term debt	-41,455		-109,955		-146,573
Line of credit borrowings (repayments), net	-187,000		-48,000		228,000
Payment of common stock dividend	-87,602		-87,490		-87,274
Other	-170		-822		-1,514
Net Cash provided by (used in) Financing Activities	25,289		-40,824		43,889
Unrestricted Cash and Temporary Cash Investments:	'		'		'
Net change for the period	51,296		-13,142		-59,282
Balance at beginning of period	17,857		30,999		90,281
Balance at end of period	69,153		17,857		30,999
UIL Holdings Corporation [Member]	'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'
Net Cash provided by Operating Activities	122,285		89,875		162,538
Cash Flows from Investing Activities	'		'		'
Acquisition of Gas Companies	0		0		11,211
Plant expenditures	-47,790		-29,689		-20,168
Capital contributions to subsidiaries	0		-100,000		-60,000
Intercompany loan receivable	-8,000		0		0
Other	0		304		18
Net Cash (used in) Investing Activities	-55,790		-129,385		-68,939
Cash Flows from Financing Activities	'		'		'
Issuance of common stock	206,516		1,943		200
Payments on long-term debt	0		0		-49,286
Line of credit borrowings (repayments), net	-157,000		122,000		35,000
Payment of common stock dividend	-87,602		-87,490		-87,274
Other	391		508		-107
Net Cash provided by (used in) Financing Activities	-37,695		36,961		-101,467
Unrestricted Cash and Temporary Cash Investments:	'		'		'
Net change for the period	28,800		-2,549		-7,868
Balance at beginning of period	115		2,664		10,532
Balance at end of period	$28,915		$115		$2,664

[1]	Information for segmenting total capital expenditures between Distribution and Transmission is not available. Total Electric Distribution and Transmission capital expenditures are disclosed in the Total Electric Distribution and Transmission column.

Schedule_I_Condensed_Financial5

Schedule I - Condensed Financial Statements of Registrant, Notes (Details) (UIL Holdings Corporation [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
UIL Holdings Corporation [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Dividends received from subsidiaries	$140,500,000	$73,100,000	$174,500,000
Information regarding maturities of long-term debt [Abstract]	'	'	'
2014	0	'	'
2015	0	'	'
2016	0	'	'
2017	0	'	'
2018 & thereafter	$450,000,000	'	'

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reserve for uncollectible accounts (consolidated): [Abstract]	'		'		'
Balance at beginning of period	$11,867		$10,939		$10,571
Acquired balance	0		0		0
Additions charged to costs and expenses	33,476		36,850		32,829
Additions charged to other accounts	0		0		0
Deductions	33,322	[1]	35,922	[1]	32,461	[1]
Balance at end of period	$12,021		$11,867		$10,939

[1]	Accounts written off, net of recoveries.