SEGMENT INFORMATION

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

SEGMENT INFORMATION

SEGMENT INFORMATION

Presentation:  Eversource is organized between the Electric Distribution, Electric Transmission and Natural Gas Distribution reportable segments and Other based on a combination of factors, including the characteristics of each segments' services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates.  These reportable segments represent substantially all of Eversource's total consolidated revenues.  Revenues from the sale of electricity and natural gas primarily are derived from residential, commercial and industrial customers and are not dependent on any single customer.  The Electric Distribution reportable segment includes the generation activities of PSNH and WMECO.  

The remainder of Eversource's operations is presented as Other in the tables below and primarily consists of 1) the equity in earnings of Eversource parent from its subsidiaries and intercompany interest income, both of which are eliminated in consolidation, and interest expense related to the debt of Eversource parent, 2) the revenues and expenses of Eversource Service, most of which are eliminated in consolidation, 3) the operations of CYAPC and YAEC, 4) the results of Eversource's equity method investments and 5) the results of other unregulated subsidiaries, which are not part of its core business.

Cash flows used for investments in plant included in the segment information below are cash capital expenditures that do not include amounts incurred but not paid, cost of removal, AFUDC related to equity funds, and the capitalized portions of pension expense.   

Eversource's reportable segments are determined based upon the level at which Eversource's chief operating decision maker assesses performance and makes decisions about the allocation of company resources.  Each of Eversource's subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, has one reportable segment.  Eversource's operating segments and reporting units are consistent with its reportable business segments.

The Electric Transmission segment includes a reduction to Operations and Maintenance expense of $27.5 million in 2016 for costs incurred in previous years that will be recovered in transmission rates over the period June 1, 2016 through May 31, 2017. These costs were associated with the merger of Northeast Utilities and NSTAR.

Eversource's segment information is as follows:

	For the Year Ended December 31, 2016
Eversource (Millions of Dollars)	Electric Distribution			Natural Gas Distribution			Electric Transmission			Other			Eliminations			Total
Operating Revenues	$	5,594.3		$	857.7		$	1,210.0		$	870.4		$	(893.3	)	$	7,639.1
Depreciation and Amortization	(504.7		)	(65.3		)	(185.8		)	(33.5		)	2.2			(787.1		)
Other Operating Expenses	(4,155.1		)	(628.9		)	(321.8		)	(778.1		)	891.8			(4,992.1		)
Operating Income	934.5			163.5			702.4			58.8			0.7			1,859.9
Interest Expense	(193.1		)	(41.3		)	(110.0		)	(63.5		)	6.9			(401.0		)
Interest Income	10.0			0.1			1.2			7.0			(7.3		)	11.0
Other Income, Net	4.8			0.6			18.3			1,020.1			(1,008.9		)	34.9
Income Tax (Expense)/Benefit	(288.8		)	(45.2		)	(238.2		)	16.5			0.7			(555.0		)
Net Income	467.4			77.7			373.7			1,038.9			(1,007.9		)	949.8
Net Income Attributable to Noncontrolling Interests	(4.6		)	—			(2.9		)	—			—			(7.5		)
Net Income Attributable to Common Shareholders	$	462.8		$	77.7		$	370.8		$	1,038.9		$	(1,007.9	)	$	942.3
Total Assets (as of)	$	18,367.5		$	3,303.8		$	8,751.5		$	14,493.1		$	(12,862.7	)	$	32,053.2
Cash Flows Used for Investments in Plant	$	812.6		$	255.3		$	801.0		$	108.0		$	—		$	1,976.9

	For the Year Ended December 31, 2015
Eversource (Millions of Dollars)	Electric Distribution			Natural Gas Distribution			Electric Transmission			Other			Eliminations			Total
Operating Revenues	$	5,903.6		$	995.5		$	1,069.1		$	863.6		$	(877.0	)	$	7,954.8
Depreciation and Amortization	(425.2		)	(70.5		)	(165.6		)	(29.0		)	2.1			(688.2		)
Other Operating Expenses	(4,470.2		)	(776.7		)	(314.9		)	(817.9		)	877.3			(5,502.4		)
Operating Income	1,008.2			148.3			588.6			16.7			2.4			1,764.2
Interest Expense	(186.3		)	(36.9		)	(105.8		)	(48.0		)	4.6			(372.4		)
Interest Income	5.7			0.1			1.6			4.4			(5.1		)	6.7
Other Income, Net	7.2			0.8			14.5			977.8			(972.8		)	27.5
Income Tax (Expense)/Benefit	(322.8		)	(40.1		)	(191.6		)	14.5			—			(540.0		)
Net Income	512.0			72.2			307.3			965.4			(970.9		)	886.0
Net Income Attributable to Noncontrolling Interests	(4.7		)	—			(2.8		)	—			—			(7.5		)
Net Income Attributable to Common Shareholders	$	507.3		$	72.2		$	304.5		$	965.4		$	(970.9	)	$	878.5
Total Assets (as of)	$	17,981.3		$	3,104.5		$	8,019.3		$	13,256.7		$	(11,781.5	)	$	30,580.3
Cash Flows Used for Investments in Plant	$	718.9		$	182.2		$	749.1		$	73.9		$	—		$	1,724.1

	For the Year Ended December 31, 2014
Eversource (Millions of Dollars)	Electric Distribution			Natural Gas Distribution			Electric Transmission			Other			Eliminations			Total
Operating Revenues	$	5,663.4		$	1,007.3		$	1,018.2		$	790.9		$	(737.9	)	$	7,741.9
Depreciation and Amortization	(384.6		)	(68.1		)	(150.5		)	(42.1		)	19.9			(625.4		)
Other Operating Expenses	(4,366.2		)	(786.7		)	(302.1		)	(748.0		)	719.3			(5,483.7		)
Operating Income	912.6			152.5			565.6			0.8			1.3			1,632.8
Interest Expense	(191.6		)	(34.0		)	(104.1		)	(36.6		)	4.2			(362.1		)
Interest Income	5.1			—			0.9			3.6			(3.6		)	6.0
Other Income, Net	10.7			0.2			10.3			916.0			(918.6		)	18.6
Income Tax (Expense)/Benefit	(269.7		)	(46.4		)	(174.5		)	22.3			—			(468.3		)
Net Income	467.1			72.3			298.2			906.1			(916.7		)	827.0
Net Income Attributable to Noncontrolling Interests	(4.7		)	—			(2.8		)	—			—			(7.5		)
Net Income Attributable to Common Shareholders	$	462.4		$	72.3		$	295.4		$	906.1		$	(916.7	)	$	819.5
Cash Flows Used for Investments in Plant	$	645.2		$	176.7		$	731.6		$	50.2		$	—		$	1,603.7