XML 63 R53.htm IDEA: XBRL DOCUMENT v3.23.3
Risk Management Activities (Schedule of Derivative Instruments in Statement of Financial Position, Fair Value) (Details) - USD ($)
$ in Millions
Sep. 30, 2023
Dec. 31, 2022
Risk Management Assets Current    
Derivatives, Fair Value [Line Items]    
Risk management assets $ 3.7 $ 18.8
Risk Management Assets Noncurrent    
Derivatives, Fair Value [Line Items]    
Risk management assets 34.7 66.0
Risk Management Liabilities Current    
Derivatives, Fair Value [Line Items]    
Risk management liabilities 1.8 1.1
Risk Management Liabilities Noncurrent    
Derivatives, Fair Value [Line Items]    
Risk management liabilities 1.4 1.9
Commodity Price Risk Programs | Risk Management Assets Current    
Derivatives, Fair Value [Line Items]    
Risk management assets 3.7 18.8
Commodity Price Risk Programs | Risk Management Assets Noncurrent    
Derivatives, Fair Value [Line Items]    
Risk management assets 34.7 66.0
Commodity Price Risk Programs | Risk Management Liabilities Current    
Derivatives, Fair Value [Line Items]    
Risk management liabilities 1.8 1.1
Commodity Price Risk Programs | Risk Management Liabilities Noncurrent    
Derivatives, Fair Value [Line Items]    
Risk management liabilities $ 1.4 $ 1.9