v3.26.1
Debt - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Debt Instrument [Line Items]    
Variable rate 1.25%  
Capitalization ratio, Maximum 60.00%  
Capitalization ratio, Actual 23.90%  
Funds available under revolving credit facility $ 1,500,000,000  
Other debt 117,000,000 $ 129,000,000
Outstanding letters of credit under various bilateral letter of credit facilities 909,000,000  
Carrying value of Unsecured Senior Notes $ 1,589,000,000 1,589,000,000
Revolving Credit Facility [Member]    
Debt Instrument [Line Items]    
Line of credit facility, maturity date Sep. 12, 2030  
Line of credit facility current borrowing capacity $ 1,500,000,000  
Credit facility, extendable borrowing capacity $ 2,500,000,000  
Variable rate basis Secured Overnight Financing Rate (SOFR), Euro Interbank Offered Rate (EURIBOR), Sterling Overnight Index Average (SONIA), Canadian Overnight Repo Rate Average (CORRA), or Norwegian Interbank Offered Rate (NIBOR),  
Outstanding letters of credit issued $ 0  
Foreign Line of Credit [Member]    
Debt Instrument [Line Items]    
Line of credit facility current borrowing capacity $ 150,000,000  
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] us-gaap:SecuredOvernightFinancingRateSofrMember  
Variable rate 1.40%  
Additional line of credit facility borrowing capacity $ 120,000,000  
Line of credit facility, repayment date 2032-06  
Debt to equity ratio maximum 75.00%  
Borrowings $ 78,000,000  
First payment 12,000,000  
Current Minority Interest Partners [Member]    
Debt Instrument [Line Items]    
Other debt 38,000,000  
Other debt due in next twelve months 2,000,000  
Unsecured Debt [Member] | Fair Value, Inputs, Level 2 [Member]    
Debt Instrument [Line Items]    
Fair value of Unsecured Senior Notes $ 1,345,000,000 $ 1,353,000,000