Hedging Activities and Fair Value Measurements, Recurring Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financial assets [Abstract]
Value before application of CME Rule 814	$ 628	$ 728
Impact of CME Rule 814	(246)	(278)
Total commodity derivatives	382	450
Total	382	450
Financial liabilities [Abstract]
Interest rate derivatives		31
Commodity derivatives:
Value before application of CME Rule 814	680	625
Impact of CME Rule 814	(296)	(154)
Total commodity derivatives	384	471
Total	384	502
Net value before application of CME Rule 814 to commodity hedging portfolio	(52)
Level 1 [Member]
Financial assets [Abstract]
Value before application of CME Rule 814	283	431
Impact of CME Rule 814	(89)	(147)
Total commodity derivatives	194	284
Total	194	284
Financial liabilities [Abstract]
Interest rate derivatives		0
Commodity derivatives:
Value before application of CME Rule 814	383	317
Impact of CME Rule 814	(170)	(22)
Total commodity derivatives	213	295
Total	213	295
Level 2 [Member]
Financial assets [Abstract]
Value before application of CME Rule 814	345	297
Impact of CME Rule 814	(157)	(131)
Total commodity derivatives	188	166
Total	188	166
Financial liabilities [Abstract]
Interest rate derivatives		31
Commodity derivatives:
Value before application of CME Rule 814	297	308
Impact of CME Rule 814	(126)	(132)
Total commodity derivatives	171	176
Total	171	207
Level 3 [Member]
Financial assets [Abstract]
Value before application of CME Rule 814	0	0
Impact of CME Rule 814	0	0
Total commodity derivatives	0	0
Total	0	0
Financial liabilities [Abstract]
Interest rate derivatives		0
Commodity derivatives:
Value before application of CME Rule 814	0	0
Impact of CME Rule 814	0	0
Total commodity derivatives	0	0
Total	$ 0	$ 0