v3.26.1
Fair Value Measurements (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Cash $ 662 $ 629
Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Cash equivalents:    
Cost Basis 2,480 1,982
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 2,480 1,982
U.S. and Canadian government obligations | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Cash equivalents:    
Cost Basis 198 284
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 198 284
Other debt securities | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Cash equivalents:    
Cost Basis 1,620 1,069
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 1,620 1,069
Nonqualified employee benefit trusts    
Cash equivalents:    
Cost Basis 15 15
Unrealized Gains 3 3
Unrealized Losses 0 0
Fair Value $ 18 $ 18