v3.25.0.1
Pension Plans and Other Postretirement Benefits - Fair Value of Pension Plan Assets (Details) - Pension Plan - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 5,188 $ 5,379 $ 5,346
Total Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,351 4,352  
Total Fair Value, Inputs, Level 1, 2 and 3 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 99 81  
Total Fair Value, Inputs, Level 1, 2 and 3 | Total debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,429 3,406  
Total Fair Value, Inputs, Level 1, 2 and 3 | U.S. government securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 487 522  
Total Fair Value, Inputs, Level 1, 2 and 3 | States, municipalities and political subdivisions      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 70 94  
Total Fair Value, Inputs, Level 1, 2 and 3 | U.S. corporate securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,753 2,649  
Total Fair Value, Inputs, Level 1, 2 and 3 | Foreign securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 98 106  
Total Fair Value, Inputs, Level 1, 2 and 3 | Residential mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 7 17  
Total Fair Value, Inputs, Level 1, 2 and 3 | Commercial mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 9 9  
Total Fair Value, Inputs, Level 1, 2 and 3 | Other asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4 8  
Total Fair Value, Inputs, Level 1, 2 and 3 | Redeemable preferred securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1 1  
Total Fair Value, Inputs, Level 1, 2 and 3 | Total equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 42 184  
Total Fair Value, Inputs, Level 1, 2 and 3 | U.S. domestic      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 30 150  
Total Fair Value, Inputs, Level 1, 2 and 3 | International      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 12 34  
Total Fair Value, Inputs, Level 1, 2 and 3 | Other investments      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 781 681  
Total Fair Value, Inputs, Level 1, 2 and 3 | Private real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 276 290  
Total Fair Value, Inputs, Level 1, 2 and 3 | Common/collective trusts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 502 405  
Total Fair Value, Inputs, Level 1, 2 and 3 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3 (14)  
Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 555 714  
Level 1 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 32 12  
Level 1 | Total debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 481 518  
Level 1 | U.S. government securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 481 518  
Level 1 | States, municipalities and political subdivisions      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | U.S. corporate securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Foreign securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Residential mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Commercial mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Other asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Redeemable preferred securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Total equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 42 184  
Level 1 | U.S. domestic      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 30 150  
Level 1 | International      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 12 34  
Level 1 | Other investments      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Private real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Common/collective trusts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 1 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,519 3,348  
Level 2 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 67 69  
Level 2 | Total debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,947 2,888  
Level 2 | U.S. government securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 6 4  
Level 2 | States, municipalities and political subdivisions      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 70 94  
Level 2 | U.S. corporate securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,752 2,649  
Level 2 | Foreign securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 98 106  
Level 2 | Residential mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 7 17  
Level 2 | Commercial mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 9 9  
Level 2 | Other asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4 8  
Level 2 | Redeemable preferred securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1 1  
Level 2 | Total equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 2 | U.S. domestic      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 2 | International      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 2 | Other investments      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 505 391  
Level 2 | Private real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 2 | Common/collective trusts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 502 405  
Level 2 | Common/collective trusts, Equity Securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets, investment within plan asset category, amount 288 114  
Level 2 | Common/collective trusts, Debt Securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets, investment within plan asset category, amount 214 291  
Level 2 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3 (14)  
Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 277 290  
Level 3 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Total debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1 0  
Level 3 | U.S. government securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | States, municipalities and political subdivisions      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | U.S. corporate securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1 0  
Level 3 | Foreign securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Residential mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Commercial mortgage-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Other asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Redeemable preferred securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Total equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | U.S. domestic      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | International      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Other investments      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 276 290  
Level 3 | Private real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 276 290 $ 325
Level 3 | Common/collective trusts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Level 3 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
Fair Value Measured at Net Asset Value Per Share | Other Receivables      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 267 314  
Fair Value Measured at Net Asset Value Per Share | Private equity limited partnerships      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 290 461  
Fair Value Measured at Net Asset Value Per Share | Hedge fund limited partnerships      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 280 $ 252