v3.25.2
Fair Value Measurements (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]    
Cash $ 444 $ 168
Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 1,686 1,614
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 1,686 1,614
U.S. and Canadian government obligations | Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 374 932
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 374 932
Other debt securities | Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 868 514
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 868 514
Nonqualified employee benefit trusts    
Cash equivalents:    
Cost Basis 15 15
Unrealized Gains 2 2
Unrealized Losses 0 0
Fair Value $ 17 $ 17