XML 54 R43.htm IDEA: XBRL DOCUMENT v3.25.1
Fair Value Measurements (Details) - USD ($)
$ in Millions
Mar. 31, 2025
Dec. 31, 2024
Schedule of Investments [Line Items]    
Cash $ 206 $ 168
Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 1,406 1,614
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 1,406 1,614
U.S. and Canadian government obligations | Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 707 932
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 707 932
Other debt securities | Cash and Cash Equivalents    
Cash equivalents:    
Cost Basis 493 514
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 493 514
Nonqualified employee benefit trusts    
Cash equivalents:    
Cost Basis 16 15
Unrealized Gains 1 2
Unrealized Losses 0 0
Fair Value $ 17 $ 17