v3.26.1
Fair Value - Schedule of Recurring Fair Value Measurements (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Assets    
Cash equivalents $ 16 $ 16
Equity securities 1,072 1,105
Debt securities 775 777
Receivables (payables), net 6 2
NDT funds 1,869 1,900
Derivative assets, netting (567) (396)
Total assets 1,912 1,960
Liabilities    
Derivative liabilities, netting (618) (440)
Total liabilities 299 168
Commodity derivatives    
Assets    
Derivative assets, netting (567) (396)
Derivative assets, total 42 60
Liabilities    
Derivative liabilities, netting (618) (440)
Derivative liabilities, total 288 156
Interest rate derivatives    
Assets    
Derivative assets, total 1 0
Liabilities    
Derivative liabilities, total 11 12
U.S. government debt securities    
Assets    
Debt securities 384 399
Municipal debt securities    
Assets    
Debt securities 97 101
Corporate debt securities    
Assets    
Debt securities 294 277
Level 1    
Assets    
Cash equivalents 0 0
Equity securities 838 871
NDT funds 1,102 1,168
Total assets 1,616 1,529
Liabilities    
Total liabilities 591 407
Level 1 | Commodity derivatives    
Assets    
Derivative assets 514 361
Liabilities    
Derivative liabilities 591 407
Level 1 | Interest rate derivatives    
Assets    
Derivative assets, total 0 0
Liabilities    
Derivative liabilities 0 0
Level 1 | U.S. government debt securities    
Assets    
Debt securities 264 297
Level 1 | Municipal debt securities    
Assets    
Debt securities 0 0
Level 1 | Corporate debt securities    
Assets    
Debt securities 0 0
Level 2    
Assets    
Cash equivalents 0 0
Equity securities 0 0
NDT funds 511 480
Total assets 607 575
Liabilities    
Total liabilities 326 201
Level 2 | Commodity derivatives    
Assets    
Derivative assets 95 95
Liabilities    
Derivative liabilities 315 189
Level 2 | Interest rate derivatives    
Assets    
Derivative assets, total 1 0
Liabilities    
Derivative liabilities 11 12
Level 2 | U.S. government debt securities    
Assets    
Debt securities 120 102
Level 2 | Municipal debt securities    
Assets    
Debt securities 97 101
Level 2 | Corporate debt securities    
Assets    
Debt securities 294 277
NAV    
Assets    
Cash equivalents 16 16
Equity securities 234 234
NDT funds 250 250
Total assets 250 250
Liabilities    
Total liabilities 0 0
NAV | Commodity derivatives    
Assets    
Derivative assets 0 0
Liabilities    
Derivative liabilities 0 0
NAV | Interest rate derivatives    
Assets    
Derivative assets, total 0 0
Liabilities    
Derivative liabilities 0 0
NAV | U.S. government debt securities    
Assets    
Debt securities 0 0
NAV | Municipal debt securities    
Assets    
Debt securities 0 0
NAV | Corporate debt securities    
Assets    
Debt securities $ 0 $ 0