SEGMENT INFORMATION (Tables)

9 Months Ended

Sep. 30, 2019

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, 2019 and 2018:

	Utility Operations
(in millions)	Wisconsin		Illinois		Other States			Total Utility Operations		Electric Transmission		Non-Utility Energy Infrastructure		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Three Months Ended
September 30, 2019
External revenues	$	1,339.3	$	198.0	$	48.9		$	1,586.2	$	—	$	20.5	$	1.3		$	—		$	1,608.0
Intersegment revenues	—		—		—			—		—		98.9		—			(98.9		)	—
Other operation and maintenance	400.2		101.8		22.0			524.0		—		3.9		1.3			—			529.2
Depreciation and amortization	155.6		45.7		6.8			208.1		—		23.3		6.0			(3.6		)	233.8
Operating income (loss)	290.8		24.8		(2.2		)	313.4		—		90.3		(6.0		)	(86.8		)	310.9
Equity in earnings of transmission affiliates	—		—		—			—		38.7		—		—			—			38.7
Interest expense	142.9		14.7		2.3			159.9		3.0		15.5		35.9			(88.5		)	125.8

	Utility Operations
(in millions)	Wisconsin		Illinois		Other States			Total Utility Operations		Electric Transmission		Non-Utility Energy Infrastructure		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Three Months Ended
September 30, 2018
External revenues	$	1,388.7	$	197.9	$	50.2		$	1,636.8	$	—	$	4.5	$	2.4		$	—		$	1,643.7
Intersegment revenues	—		—		—			—		—		110.7		—			(110.7		)	—
Other operation and maintenance	525.0		104.5		23.0			652.5		—		3.0		(4.4		)	(98.0		)	553.1
Depreciation and amortization	137.2		43.0		6.4			186.6		—		19.1		7.1			—			212.8
Operating income (loss)	201.4		15.5		(5.4		)	211.5		—		91.6		(0.4		)	—			302.7
Equity in earnings of transmission affiliates	—		—		—			—		33.7		—		—			—			33.7
Interest expense	49.6		12.8		2.1			64.5		—		15.9		32.9			(1.3		)	112.0

	Utility Operations
(in millions)	Wisconsin		Illinois		Other States		Total Utility Operations		Electric Transmission		Non-Utility Energy Infrastructure		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Nine Months Ended
September 30, 2019
External revenues	$	4,226.0	$	977.4	$	302.9	$	5,506.3	$	—	$	65.4	$	3.9		$	—		$	5,575.6
Intersegment revenues	—		—		—		—		—		305.1		—			(305.1		)	—
Other operation and maintenance	1,156.8		337.0		73.0		1,566.8		—		14.5		2.1			—			1,583.4
Depreciation and amortization	459.5		135.2		20.0		614.7		—		68.8		18.4			(11.8		)	690.1
Operating income (loss)	922.8		205.3		43.9		1,172.0		—		274.3		(17.0		)	(261.0		)	1,168.3
Equity in earnings of transmission affiliates	—		—		—		—		111.7		—		—			—			111.7
Interest expense	429.0		43.4		6.5		478.9		8.3		46.7		107.5			(267.1		)	374.3

	Utility Operations
(in millions)	Wisconsin		Illinois		Other States		Total Utility Operations		Electric Transmission		Non-Utility Energy Infrastructure		Corporate and Other			Reconciling Eliminations			WEC Energy Group Consolidated
Nine Months Ended
September 30, 2018
External revenues	$	4,303.3	$	973.2	$	292.5	$	5,569.0	$	—	$	26.8	$	6.9		$	—		$	5,602.7
Intersegment revenues	—		—		—		—		—		323.5		—			(323.5		)	—
Other operation and maintenance	1,495.9		320.8		74.5		1,891.2		—		9.2		(2.5		)	(295.2		)	1,602.7
Depreciation and amortization	406.9		125.7		17.5		550.1		—		55.7		22.3			—			628.1
Operating income (loss)	670.2		204.8		38.9		913.9		—		277.0		(12.3		)	—			1,178.6
Equity in earnings of transmission affiliates	—		—		—		—		95.2		—		—			—			95.2
Interest expense	147.5		37.4		6.3		191.2		—		48.0		91.2			(3.2		)	327.2