v3.26.1
Revenue from contracts with customers transaction prices allocated to significant unsatisfied remaining performance obligations and timing of when performance obligations expected to be satisfied (Detail)
$ in Millions
Mar. 31, 2026
USD ($)
Electricity and Natural Gas [Member]  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 22,223
Electricity and Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 3,413
Performance obligations expected to be satisfied, period 1 year
Electricity and Natural Gas [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 18,810
Performance obligations expected to be satisfied, period
Other Sales and Service Contracts [Member]  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 14,484
Other Sales and Service Contracts [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 3,971
Performance obligations expected to be satisfied, period 1 year
Other Sales and Service Contracts [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Transaction price allocated to remaining performance obligations $ 10,513
Performance obligations expected to be satisfied, period