v3.26.1
Derivative Financial Instruments (Tables)
 6 Months Ended
Jun. 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 June 30, 2026, and December 31, 2025. As of June 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)
June 30, 2026December 31, 2025
CommodityAmeren MissouriAmeren IllinoisAmerenAmeren MissouriAmeren IllinoisAmeren
Fuel oils (in gallons)21 — 21 25 — 25 
Natural gas (in MMBtu)58 226 284 46 217 263 
Power (in MWhs)7 7 14 — 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 June 30, 2026, and December 31, 2025:
June 30, 2026December 31, 2025
CommodityBalance Sheet LocationAmeren
Missouri		Ameren
Illinois		AmerenAmeren
Missouri		Ameren
Illinois		Ameren
Fuel oilsOther current assets$7 $— $7 $— $— $— 
Other assets4 — 4 — — — 
Natural gasOther current assets— 1 1 1 1 2 
Other assets— 1 1 — 3 3 
PowerOther current assets17 — 17 11 — 11 
Other assets15 — 15 — — — 
Total assets$43 $2 $45 $12 $4 $16 
Fuel oilsOther current liabilities$— $— $— $3 $— $3 
Other deferred credits and liabilities— — — 2 — 2 
Natural GasOther current liabilities7 28 35 5 21 26 
Other deferred credits and liabilities8 19 27 5 11 16 
PowerOther current liabilities— 33 33 — 24 24 
Other deferred credits and liabilities1 30 31 — 55 55 
Total liabilities$16 $110 $126 $15 $111 $126