Derivative Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Open Gross Derivative Volumes By Commodity Type

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of September 30, 2019, and December 31, 2018. As of September 30, 2019, these contracts extended through October 2022, March 2024, and May 2032 for fuel oils, natural gas, and power, respectively.

	Quantity (in millions)
	2019			2018
Commodity	Ameren Missouri	Ameren Illinois	Ameren	Ameren Missouri	Ameren Illinois	Ameren
Fuel oils (in gallons)(a)	63	—	63	66	—	66
Natural gas (in mmbtu)	20	142	162	19	154	173
Power (in megawatthours)	4	8	12	1	8	9

(a)

Consists of ultra-low-sulfur diesel products.

Derivative Instruments Carrying Value

The following table presents the carrying value and balance sheet location of all derivative commodity contracts, none of which were designated as hedging instruments, as of September 30, 2019, and December 31, 2018:

			September 30, 2019					December 31, 2018
	Balance Sheet Location		Ameren Missouri		Ameren Illinois		Ameren			Ameren Missouri		Ameren Illinois		Ameren
Fuel oils	Other current assets	$	4	$	—	$	4		$	3	$	—	$	3
	Other assets		2		—		2			5		—		5
Natural gas	Other current assets		—		2		2			—		1		1
	Other assets		—		1		1			—		2		2
Power	Other current assets		8		—		8			4		—		4
	Other assets		4		—		4			—		—		—
	Total assets	$	18	$	3	$	21		$	12	$	3	$	15
Fuel oils	Other current liabilities	$	7	$	—	$	7		$	4	$	—	$	4
	Other deferred credits and liabilities		5		—		5			9		—		9
Natural gas	Other current liabilities		3		12		15			4		8		12
	Other deferred credits and liabilities		1		7		8			1		6		7
Power	Other current liabilities		3		15		18			4		14		18
	Other deferred credits and liabilities		1		189		190			—		169		169
	Total liabilities	$	20	$	223	$	243		$	22	$	197	$	219