Hedging Activities and Fair Value Measurements, Recurring Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financial assets [Abstract]
Interest rate derivatives		$ 26
Value before application of CME Rule 814	$ 712	1,336
Impact of CME Rule 814	(483)	(850)
Total commodity derivatives	229	486
Total	229	512
Commodity derivatives:
Value before application of CME Rule 814	860	1,213
Impact of CME Rule 814	(529)	(801)
Total commodity derivatives	331	412
Total	331	412
Net value before application of CME Rule 814 to commodity hedging portfolio	(148)
Level 1 [Member]
Financial assets [Abstract]
Interest rate derivatives		0
Value before application of CME Rule 814	164	166
Impact of CME Rule 814	(139)	(161)
Total commodity derivatives	25	5
Total	25	5
Commodity derivatives:
Value before application of CME Rule 814	109	95
Impact of CME Rule 814	(87)	(90)
Total commodity derivatives	22	5
Total	22	5
Level 2 [Member]
Financial assets [Abstract]
Interest rate derivatives		26
Value before application of CME Rule 814	547	1,170
Impact of CME Rule 814	(344)	(689)
Total commodity derivatives	203	481
Total	203	507
Commodity derivatives:
Value before application of CME Rule 814	751	1,118
Impact of CME Rule 814	(442)	(711)
Total commodity derivatives	309	407
Total	309	407
Level 3 [Member]
Financial assets [Abstract]
Interest rate derivatives		0
Value before application of CME Rule 814	1	0
Impact of CME Rule 814	0	0
Total commodity derivatives	1	0
Total	1	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