Hedging Activities and Fair Value Measurements, Recurring Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Financial assets [Abstract]
Interest rate derivatives		$ 26
Value before application of CME Rule 814	$ 728	1,336
Impact of CME Rule 814	(278)	(850)
Total commodity derivatives	450	486
Total	450	512
Financial liabilities [Abstract]
Interest rate derivatives	31
Commodity derivatives:
Value before application of CME Rule 814	625	1,213
Impact of CME Rule 814	(154)	(801)
Total commodity derivatives	471	412
Total	502	412
Net value before application of CME Rule 814 to commodity hedging portfolio	103
Level 1 [Member]
Financial assets [Abstract]
Interest rate derivatives		0
Value before application of CME Rule 814	431	166
Impact of CME Rule 814	(147)	(161)
Total commodity derivatives	284	5
Total	284	5
Financial liabilities [Abstract]
Interest rate derivatives	0
Commodity derivatives:
Value before application of CME Rule 814	317	95
Impact of CME Rule 814	(22)	(90)
Total commodity derivatives	295	5
Total	295	5
Level 2 [Member]
Financial assets [Abstract]
Interest rate derivatives		26
Value before application of CME Rule 814	297	1,170
Impact of CME Rule 814	(131)	(689)
Total commodity derivatives	166	481
Total	166	507
Financial liabilities [Abstract]
Interest rate derivatives	31
Commodity derivatives:
Value before application of CME Rule 814	308	1,118
Impact of CME Rule 814	(132)	(711)
Total commodity derivatives	176	407
Total	207	407
Level 3 [Member]
Financial assets [Abstract]
Interest rate derivatives		0
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