SEGMENT INFORMATION

Ameren has four segments: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. The Ameren Missouri segment includes all of the operations of Ameren Missouri. Ameren Illinois Electric Distribution consists of the electric distribution business of Ameren Illinois. Ameren Illinois Natural Gas consists of the natural gas business of Ameren Illinois. Ameren Transmission primarily consists of the aggregated electric transmission businesses of Ameren Illinois and ATXI. The category called Other primarily includes Ameren (parent) activities and Ameren Services.

Ameren Missouri has one segment. Ameren Illinois has three segments: Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission. See Note 1 – Summary of Significant Accounting Policies for additional information regarding the operations of Ameren Missouri, Ameren Illinois, and ATXI.

Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois at each Ameren Illinois segment. Common operating expenses, miscellaneous income and expenses, interest charges, and income tax expense are allocated by Ameren Illinois to each Ameren Illinois segment based on certain factors, which primarily relate to the nature of the cost. Additionally, Ameren Illinois Transmission earns revenue from transmission services provided to Ameren Illinois Electric Distribution, other retail electric suppliers, and wholesale customers. The transmission expense for Illinois customers who have elected to purchase their power from Ameren Illinois is recovered through a cost recovery mechanism with no net effect on Ameren Illinois Electric Distribution earnings, as costs are offset by corresponding revenues. Transmission revenues from these transactions are reflected in Ameren Transmission’s and Ameren Illinois Transmission’s operating revenues. An intersegment elimination at Ameren and Ameren Illinois occurs to eliminate these transmission revenues and expenses.

The following tables present revenues, net income attributable to common shareholders, and capital expenditures by segment at Ameren and Ameren Illinois for the three months ended March 31, 2019 and 2018. Ameren, Ameren Missouri, and Ameren Illinois management review segment capital expenditure information rather than any individual or total asset amount.

Ameren



Three Months	Ameren Missouri		Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Transmission			Other		Intersegment Eliminations			Ameren
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
2018
External revenues	$	784	$	399	$	311	$	91		$	—	$	—		$	1,585
Intersegment revenues	8		1		—		13			—		(22		)	—
Net income attributable to Ameren common shareholders	38		33		42		37		^(a)	1		—			151
Capital expenditures	249		122		60		145			7		(4		)	579


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

Ameren Illinois



Three Months	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas		Ameren Illinois Transmission		Intersegment Eliminations			Ameren Illinois
2019
External revenues	$	387	$	320	$	55	$	—		$	762
Intersegment revenues	—		—		15		(15		)	—
Net income available to common shareholder	36		57		27		—			120
Capital expenditures	124		51		92		—			267
2018
External revenues	$	400	$	311	$	49	$	—		$	760
Intersegment revenues	—		—		13		(13		)	—
Net income available to common shareholder	33		42		20		—			95
Capital expenditures	122		60		118		—			300

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the three months ended March 31, 2019 and 2018. 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



Three Months	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Transmission		Other		Intersegment Eliminations			Ameren
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 gas revenues	$	54		$	—	$	320		$	—	$	—	$	—		$	374
Total revenues^(a)	$	758		$	387	$	320		$	114	$	—	$	(23	)	$	1,556
2018
Residential	$	332		$	219	$	—		$	—	$	—	$	—		$	551
Commercial	252			124		—			—		—		—			376
Industrial	61			35		—			—		—		—			96
Other	96			22		—			104		—		(22		)	200
Total electric revenues	$	741		$	400	$	—		$	104	$	—	$	(22	)	$	1,223
Residential	$	41		$	—	$	243		$	—	$	—	$	—		$	284
Commercial	16			—		67			—		—		—			83
Industrial	2			—		6			—		—		—			8
Other	(8		)	—		(5		)	—		—		—			(13		)
Total gas revenues	$	51		$	—	$	311		$	—	$	—	$	—		$	362
Total revenues^(a)	$	792		$	400	$	311		$	104	$	—	$	(22	)	$	1,585


(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, 2019 and 2018:



Three Months	Ameren Missouri			Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Transmission			Ameren
2019
Revenues from alternative revenue programs	$	15		$	22	$	(3	)	$	(5	)	$	29
Other revenues not from contracts with customers	5			3		1			—			9
2018
Revenues from alternative revenue programs	$	(4	)	$	31	$	(3	)	$	(4	)	$	20
Other revenues not from contracts with customers	14			10		1			—			25

Ameren Illinois



Three Months	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Illinois Transmission		Intersegment Eliminations			Total Ameren Illinois
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
2018
Residential	$	219	$	243		$	—	$	—		$	462
Commercial	124		67			—		—			191
Industrial	35		6			—		—			41
Other	22		(5		)	62		(13		)	66
Total revenues^(a)	$	400	$	311		$	62	$	(13	)	$	760


(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, 2019 and 2018:



Three Months	Ameren Illinois Electric Distribution		Ameren Illinois Natural Gas			Ameren Illinois Transmission			Ameren Illinois
2019
Revenues from alternative revenue programs	$	22	$	(3	)	$	(5	)	$	14
Other revenues not from contracts with customers	3		1			—			4
2018
Revenues from alternative revenue programs	$	31	$	(3	)	$	(4	)	$	24
Other revenues not from contracts with customers	10		1			—			11