XML 116 R103.htm IDEA: XBRL DOCUMENT v3.8.0.1
Commitments and Contingencies - Investments in Affiliates and Other Entities (Detail)
$ in Millions
39 Months Ended
Dec. 31, 2017
USD ($)
Aug. 31, 2024
USD ($)
May 31, 2022
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2014
kV
substation
km
Other Commitments, Planned Oil and Gas Infrastructure Projects            
Other Commitments [Line Items]            
Outstanding capital commitment $ 16.9          
Scenario, Forecast | Other Commitments, Planned Oil and Gas Infrastructure Projects            
Other Commitments [Line Items]            
Outstanding capital commitment     $ 2.1   $ 14.8  
Scenario, Forecast | Capital for Infrastructure Projects            
Other Commitments [Line Items]            
Outstanding capital commitment   $ 80.0        
EPC Electric Transmission Project            
Other Commitments [Line Items]            
Length of electrical transmission line to be constructed under contract | km           500
Number of substations | substation           2
Voltage of substations | kV           500
Aggregate contributions to this unconsolidated affiliate 66.7          
Proceeds from return of capital $ 64.4          
EPC Electric Transmission Project | Scenario, Forecast            
Other Commitments [Line Items]            
Outstanding capital commitment       $ 25.2    
Infrastructure Investors Partnership | Scenario, Forecast | Capital for Infrastructure Projects            
Other Commitments [Line Items]            
Outstanding capital commitment   $ 1,000.0