Segment Information (Tables)

9 Months Ended

Sep. 30, 2016

Segment Reporting [Abstract]

Financial information of reportable segments

The following tables show summarized financial information related to our reportable segments for the three and nine months ended September 30, 2016 and 2015:

	Regulated Operations
(in millions)	Wisconsin		Illinois		Other States			Electric Transmission		Total Regulated Operations		We Power		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Three Months Ended
September 30, 2016
External revenues	$	1,470.6	$	181.8	$	49.9		$	—	$	1,702.3	$	6.2	$	4.0		$	—		$	1,712.5
Intersegment revenues	—		—		—			—		—		105.0		—			(105.0		)	—
Other operation and maintenance	498.2		105.9		21.2			—		625.3		0.4		(3.2		)	(105.0		)	517.5
Depreciation and amortization	124.5		33.5		5.2			—		163.2		17.1		11.3			—			191.6
Operating income (loss)	299.1		11.7		(1.0		)	—		309.8		93.7		(4.5		)	—			399.0
Equity in earnings of transmission affiliate	—		—		—			38.3		38.3		—		—			—			38.3
Interest expense	44.6		9.3		1.9			—		55.8		15.6		29.7			(2.0		)	99.1

	Regulated Operations
(in millions)	Wisconsin		Illinois		Other States			Electric Transmission		Total Regulated Operations		We Power		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Three Months Ended
September 30, 2015
External revenues	$	1,439.7	$	171.8	$	49.6		$	—	$	1,661.1	$	9.7	$	27.9		$	—		$	1,698.7
Intersegment revenues	2.6		—		—			—		2.6		101.0		—			(103.6		)	—
Other operation and maintenance	501.9		101.0		23.1			—		626.0		0.6		12.9			(103.6		)	535.9
Depreciation and amortization	117.5		31.2		4.9			—		153.6		16.9		6.1			(0.1		)	176.5
Operating income (loss)	256.6		3.5		(3.7		)	—		256.4		93.2		(3.9		)	—			345.7
Equity in earnings of transmission affiliate	—		—		—			40.0		40.0		—		—			—			40.0
Interest expense	45.9		9.7		2.6			—		58.2		15.8		31.3			(2.1		)	103.2

	Regulated Operations
(in millions)	Wisconsin		Illinois		Other States		Electric Transmission		Total Regulated Operations		We Power		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Nine Months Ended
September 30, 2016
External revenues	$	4,354.9	$	853.1	$	262.3	$	—	$	5,470.3	$	18.7	$	20.3		$	—		$	5,509.3
Intersegment revenues	0.3		—		—		—		0.3		317.1		—			(317.4		)	—
Other operation and maintenance	1,477.3		340.0		80.6		—		1,897.9		3.5		(13.0		)	(317.4		)	1,571.0
Depreciation and amortization	370.1		99.4		15.5		—		485.0		51.1		33.4			—			569.5
Operating income (loss)	841.3		171.3		33.1		—		1,045.7		281.1		(6.4		)	—			1,320.4
Equity in earnings of transmission affiliate	—		—		—		107.7		107.7		—		—			—			107.7
Interest expense	133.5		28.8		6.5		—		168.8		46.8		91.2			(6.7		)	300.1

	Regulated Operations
(in millions)	Wisconsin		Illinois		Other States			Electric Transmission		Total Regulated Operations		We Power		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Nine Months Ended
September 30, 2015
External revenues	$	3,794.7	$	171.8	$	49.6		$	—	$	4,016.1	$	30.4	$	31.3		$	—		$	4,077.8
Intersegment revenues	4.4		—		—			—		4.4		302.7		—			(307.1		)	—
Other operation and maintenance	1,239.3		101.0		23.1			—		1,363.4		3.7		93.1			(306.6		)	1,153.6
Depreciation and amortization	289.2		31.2		4.9			—		325.3		50.6		6.8			(0.1		)	382.6
Operating income (loss)	673.5		3.5		(3.7		)	—		673.3		278.9		(81.9		)	—			870.3
Equity in earnings of transmission affiliate	—		—		—			70.4		70.4		—		—			—			70.4
Interest expense	109.4		9.7		2.6			—		121.7		47.6		57.5			(2.4		)	224.4