Segment Information (Tables)

3 Months Ended

Mar. 31, 2020

Segment Reporting [Abstract]

Schedule Of Segment Reporting Information By Segment

The following tables present revenues, net income (loss) attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three months ended March 31, 2020 and 2019. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount. For additional information about our segments, see Note 16 – Segment Information under Part II, Item 8, of the Form 10-K

Ameren

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other		Intersegment Eliminations			Ameren
Three Months 2020:
External revenues	$	670		$	389	$	271	$	110		$	—	$	—		$	1,440
Intersegment revenues	10			1		—		13			—		(24		)	—
Net income (loss) attributable to Ameren common shareholders	(10		)	37		55		47		(a)	17		—			146
Capital expenditures	278			123		61		170			3		1			636
Three Months 2019:
External revenues	$	751		$	386	$	320	$	99		$	—	$	—		$	1,556
Intersegment revenues	7			1		—		15			—		(23		)	—
Net income attributable to Ameren common shareholders	39			36		57		44		(a)	15		—			191
Capital expenditures	240			124		51		121			10		(2		)	544

(a) Ameren Transmission earnings reflect an allocation of financing costs from Ameren (parent).

Ameren Illinois

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission			Intersegment Eliminations			Ameren Illinois
Three Months 2020:
External revenues	$	390	$	271	$	62		$	—		$	723
Intersegment revenues	—		—		12		(a)	(12		)	—
Net income available to common shareholder	37		55		28			—			120
Capital expenditures	123		61		140			—			324
Three Months 2019:
External revenues	$	387	$	320	$	55		$	—		$	762
Intersegment revenues	—		—		15		(a)	(15		)	—
Net income available to common shareholder	36		57		27			—			120
Capital expenditures	124		51		92			—			267

(a)

Ameren Illinois Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution.

Disaggregation of Revenue

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three months ended March 31, 2020 and 2019. Economic factors affect the nature, timing, amount, and uncertainty of revenues and cash flows in a similar manner across customer classes. Revenues from alternative revenue programs have a similar distribution among customer classes as revenues from contracts with customers. Other revenues not associated with contracts with customers are presented in the Other customer classification, along with electric transmission and off-system revenues.

Ameren

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission		Intersegment Eliminations			Ameren
Three Months 2020:
Residential	$	297		$	220	$	—	$	—	$	—		$	517
Commercial	221			126		—		—		—			347
Industrial	53			35		—		—		—			88
Other	60			9		—		123		(24		)	168
Total electric revenues	$	631		$	390	$	—	$	123	$	(24	)	$	1,120
Residential	$	33		$	—	$	213	$	—	$	—		$	246
Commercial	13			—		54		—		—			67
Industrial	1			—		3		—		—			4
Other	2			—		1		—		—			3
Total natural gas revenues	$	49		$	—	$	271	$	—	$	—		$	320
Total revenues(a)	$	680		$	390	$	271	$	123	$	(24	)	$	1,440
Three Months 2019:
Residential	$	312		$	217	$	—	$	—	$	—		$	529
Commercial	239			123		—		—		—			362
Industrial	55			34		—		—		—			89
Other	98			13		—		114		(23		)	202
Total electric revenues	$	704		$	387	$	—	$	114	$	(23	)	$	1,182
Residential	$	38		$	—	$	246	$	—	$	—		$	284
Commercial	16			—		65		—		—			81
Industrial	2			—		4		—		—			6
Other	(2		)	—		5		—		—			3
Total natural gas revenues	$	54		$	—	$	320	$	—	$	—		$	374
Total revenues(a)	$	758		$	387	$	320	$	114	$	(23	)	$	1,556

(a) The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the three months ended March 31, 2020 and 2019:

	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Transmission			Ameren
Three Months 2020:
Revenues from alternative revenue programs	$	(3	)	$	46	$	11		$	12		$	66
Other revenues not from contracts with customers	8			1		1			—			10
Three Months 2019:
Revenues from alternative revenue programs	$	15		$	22	$	(3	)	$	(5	)	$	29
Other revenues not from contracts with customers	5			3		1			—			9

Ameren Illinois

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations			Ameren Illinois
Three Months 2020:
Residential	$	220	$	213	$	—	$	—		$	433
Commercial	126		54		—		—			180
Industrial	35		3		—		—			38
Other	9		1		74		(12		)	72
Total revenues(a)	$	390	$	271	$	74	$	(12	)	$	723
Three Months 2019:
Residential	$	217	$	246	$	—	$	—		$	463
Commercial	123		65		—		—			188
Industrial	34		4		—		—			38
Other	13		5		70		(15		)	73
Total revenues(a)	$	387	$	320	$	70	$	(15	)	$	762

(a) The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the Ameren Illinois segments for the three months ended March 31, 2020 and 2019:

	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Illinois Transmission			Ameren Illinois
Three Months 2020:
Revenues from alternative revenue programs	$	46	$	11		$	10		$	67
Other revenues not from contracts with customers	1		1			—			2
Three Months 2019:
Revenues from alternative revenue programs	$	22	$	(3	)	$	(5	)	$	14
Other revenues not from contracts with customers	3		1			—			4