Hedging Activities and Fair Value Measurements, Recurring Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Financial assets [Abstract]
Interest rate derivatives		$ 26
Value before application of CME Rule 814	$ 1,131	1,336
Impact of CME Rule 814	(757)	(850)
Total commodity derivatives	374	486
Total	374	512
Commodity derivatives:
Value before application of CME Rule 814	1,041	1,213
Impact of CME Rule 814	(659)	(801)
Total commodity derivatives	382	412
Total	382	412
Net value before application of CME Rule 814 to commodity hedging portfolio	90
Level 1 [Member]
Financial assets [Abstract]
Interest rate derivatives		0
Value before application of CME Rule 814	147	166
Impact of CME Rule 814	(109)	(161)
Total commodity derivatives	38	5
Total	38	5
Commodity derivatives:
Value before application of CME Rule 814	80	95
Impact of CME Rule 814	(42)	(90)
Total commodity derivatives	38	5
Total	38	5
Level 2 [Member]
Financial assets [Abstract]
Interest rate derivatives		26
Value before application of CME Rule 814	984	1,170
Impact of CME Rule 814	(648)	(689)
Total commodity derivatives	336	481
Total	336	507
Commodity derivatives:
Value before application of CME Rule 814	961	1,118
Impact of CME Rule 814	(617)	(711)
Total commodity derivatives	344	407
Total	344	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
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