Fair Value - Summary of Recurring Fair Value Measurements (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Assets
Cash equivalents	$ 13	$ 9
Equity securities, Fair Value	1,078	1,013
Debt securities	598	579
Receivables (payables), net	(30)	(26)
NDT funds	1,659	1,575
Derivative assets, netting	(246)	(200)
Total assets	1,699	1,670
Liabilities
Derivative liabilities, netting	(268)	(257)
Less: other	0	0
Total liabilities	64	43
Commodity derivatives
Assets
Derivative assets, netting	(246)	(200)
Derivative assets, total	37	94
Liabilities
Derivative liabilities, netting	(268)	(257)
Derivative liabilities, total	64	37
Interest rate derivatives
Assets
Derivative assets, total	3	1
Liabilities
Derivative liabilities, total	0	6
U.S. Government debt securities
Assets
Debt securities	336	337
Municipal debt securities
Assets
Debt securities	83	86
Corporate debt securities
Assets
Debt securities	179	156
Level 1
Assets
Cash equivalents	0	0
Equity securities, Fair Value	718	629
NDT funds	1,054	966
Total assets	1,221	1,064
Liabilities
Less: other	0	0
Total liabilities	190	155
Level 1 | Commodity derivatives
Assets
Derivative assets	167	98
Liabilities
Derivative liabilities	190	155
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	336	337
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, Fair Value	0	0
NDT funds	262	242
Total assets	381	439
Liabilities
Less: other	0	0
Total liabilities	142	145
Level 2 | Commodity derivatives
Assets
Derivative assets	116	196
Liabilities
Derivative liabilities	142	139
Level 2 | Interest rate derivatives
Assets
Derivative assets, total	3	1
Liabilities
Derivative liabilities	0	6
Level 2 | U.S. Government debt securities
Assets
Debt securities	0	0
Level 2 | Municipal debt securities
Assets
Debt securities	83	86
Level 2 | Corporate debt securities
Assets
Debt securities	179	156
NAV
Assets
Cash equivalents	13	9
Equity securities, Fair Value	360	384
NDT funds	373	393
Total assets	373	393
Liabilities
Less: other	0	0
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