SEGMENT INFORMATION (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

Eversource's segment information is as follows:

	For the Year Ended December 31, 2017
Eversource (Millions of Dollars)	Electric Distribution			Natural Gas Distribution			Electric Transmission			Other			Eliminations			Total
Operating Revenues	$	5,542.9		$	947.3		$	1,301.7		$	946.9		$	(986.8	)	$	7,752.0
Depreciation and Amortization	(542.6		)	(72.9		)	(209.4		)	(41.1		)	2.2			(863.8		)
Other Operating Expenses	(4,046.0		)	(713.5		)	(382.6		)	(814.6		)	986.7			(4,970.0		)
Operating Income	954.3			160.9			709.7			91.2			2.1			1,918.2
Interest Expense	(186.3		)	(43.1		)	(115.1		)	(93.1		)	15.8			(421.8		)
Interest Income	7.3			0.1			1.8			15.8			(16.7		)	8.3
Other Income, Net	15.0			0.9			27.1			1,112.7			(1,086.0		)	69.7
Income Tax Expense	(288.3		)	(44.2		)	(228.7		)	(17.6		)	(0.1		)	(578.9		)
Net Income	502.0			74.6			394.8			1,109.0			(1,084.9		)	995.5
Net Income Attributable to Noncontrolling Interests	(4.6		)	—			(2.9		)	—			—			(7.5		)
Net Income Attributable to Common Shareholders	$	497.4		$	74.6		$	391.9		$	1,109.0		$	(1,084.9	)	$	988.0
Total Assets (as of)	$	19,250.4		$	3,595.2		$	9,401.2		$	18,403.8		$	(14,430.2	)	$	36,220.4
Cash Flows Used for Investments in Plant	$	1,020.7		$	298.2		$	867.6		$	161.6		$	—		$	2,348.1

	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
Cash Flows Used for Investments in Plant	$	718.9		$	182.2		$	749.1		$	73.9		$	—		$	1,724.1