v3.26.3
Derivative Financial Instruments (Tables)
 9 Months Ended
Sep. 30, 2026
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, 2026, and December 31, 2025. As of September 30, 2026, these contracts extended through October 2029, October 2032, and May 2032 for fuel oils, natural gas, and power, respectively.
Quantity (in millions, except as indicated)
September 30, 2026December 31, 2025
CommodityAmeren MissouriAmeren IllinoisAmerenAmeren MissouriAmeren IllinoisAmeren
Fuel oils (in gallons)20 — 20 25 — 25 
Natural gas (in MMBtu)56 209 265 46 217 263 
Power (in MWhs)10 6 16 — 7 7 
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 because all qualify for regulatory deferral, as of September 30, 2026, and December 31, 2025:
September 30, 2026December 31, 2025
CommodityBalance Sheet LocationAmeren
Missouri		Ameren
Illinois		AmerenAmeren
Missouri		Ameren
Illinois		Ameren
Fuel oilsOther current assets$15 $— $15 $— $— $— 
Other assets6 — 6 — — — 
Natural gasOther current assets— 2 2 1 1 2 
Other assets1 3 4 — 3 3 
PowerOther current assets14 1 15 11 — 11 
Other assets61 4 65 — — — 
Total assets$97 $10 $107 $12 $4 $16 
Fuel oilsOther current liabilities$— $— $— $3 $— $3 
Other deferred credits and liabilities— — — 2 — 2 
Natural gasMark-to-market derivative liabilities(a)30 (a)(a)21 (a)
Other current liabilities7 — 37 5 — 26 
Other deferred credits and liabilities5 8 13 5 11 16 
PowerMark-to-market derivative liabilities(a)30 (a)(a)24 (a)
Other current liabilities2 — 32 — — 24 
Other deferred credits and liabilities— 18 18 — 55 55 
Total liabilities$14 $86 $100 $15 $111 $126 
(a) Balance sheet line item not applicable to registrant.