Related Party Transactions (Tables)

3 Months Ended

Mar. 31, 2019

Related Party Transactions [Abstract]

Schedule of Related Party Transactions

The following table presents the impact on Ameren Missouri and Ameren Illinois of related-party transactions for the three months ended March 31, 2019 and 2018:

				Three Months
Agreement	Income Statement Line Item			Ameren Missouri		Ameren Illinois
Ameren Missouri power supply	Operating Revenues	2019	$	(b)	$	(a)
agreements with Ameren Illinois		2018		3		(a)
Ameren Missouri and Ameren Illinois	Operating Revenues	2019		7		1
rent and facility services		2018		5		1
Ameren Missouri and Ameren Illinois	Operating Revenues	2019		(b)		(b)
miscellaneous support services		2018		(b)		(b)
Total Operating Revenues		2019	$	7	$	1
		2018		8		1
Ameren Illinois power supply	Purchased Power	2019	$	(a)	$	(b)
agreements with Ameren Missouri		2018		(a)		3
Ameren Illinois transmission	Purchased Power	2019		(a)		(b)
services with ATXI		2018		(a)		(b)
Total Purchased Power		2019	$	(a)	$	(b)
		2018		(a)		3
Ameren Missouri and Ameren Illinois	Other Operations and Maintenance	2019	$	(b)	$	1
rent and facility services		2018		(b)		2
Ameren Services support services	Other Operations and Maintenance	2019		32		30
agreement		2018		33		30
Total Other Operations and Maintenance		2019	$	32	$	31
		2018		33		32
Money pool borrowings (advances)	Interest Charges/ Other Income, Net	2019	$	—	$	—
		2018		(b)		(b)

(a) Not applicable.

(b) Amount less than $1 million.