Fair Value Measurements and Guarantees Recurring Measurements and Additional (Details) - USD ($) $ in Millions	Mar. 31, 2023		Dec. 31, 2022
Additional disclosures:
Collateral Already Posted, Aggregate Fair Value	$ 120
Carrying Amount [Member]
Additional disclosures:
Long-term debt, including current portion	(24,412)		$ (22,554)
Guarantees	(38)		(38)
Fair Value [Member]
Additional disclosures:
Long-term debt, including current portion	(23,727)		(21,569)
Guarantees	(27)		(25)
Level 1 [Member]
Additional disclosures:
Long-term debt, including current portion	0		0
Guarantees	0		0
Collateral Already Posted, Aggregate Fair Value	120		202
Level 2 [Member]
Additional disclosures:
Long-term debt, including current portion	(23,727)		(21,569)
Guarantees	(11)		(9)
Level 3 [Member]
Additional disclosures:
Long-term debt, including current portion	0		0
Guarantees	(16)		(16)
Fair Value, Recurring [Member] | Carrying Amount [Member]
Measured on a recurring basis:
ARO Trust investments	242		230
Derivative Asset, Fair Value, Gross Asset	132	[1]	166	[2]
Derivative Liability, Fair Value, Gross Liability	(449)	[1]	(810)	[2]
Other financial assets (liabilities) – net	(1)		(5)
Fair Value, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis:
ARO Trust investments	242		230
Derivative Asset, Fair Value, Gross Asset	132	[1]	166	[2]
Derivative Liability, Fair Value, Gross Liability	(449)	[1]	(810)	[2]
Other financial assets (liabilities) – net	(1)		(5)
Fair Value, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis:
ARO Trust investments	242		230
Derivative Asset, Fair Value, Gross Asset	17	[1]	20	[2]
Derivative Liability, Fair Value, Gross Liability	(1)	[1]	(22)	[2]
Other financial assets (liabilities) – net	0		0
Fair Value, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis:
ARO Trust investments	0		0
Derivative Asset, Fair Value, Gross Asset	109	[1]	132	[2]
Derivative Liability, Fair Value, Gross Liability	(395)	[1]	(718)	[2]
Other financial assets (liabilities) – net	(1)		(5)
Fair Value, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis:
ARO Trust investments	0		0
Derivative Asset, Fair Value, Gross Asset	6	[1]	14	[2]
Derivative Liability, Fair Value, Gross Liability	(53)	[1]	(70)	[2]
Other financial assets (liabilities) – net	0		$ 0
WilTel Guarantee [Member]
Additional disclosures:
Guarantor Obligations, Maximum Exposure, Undiscounted	24
Indemnification Agreement [Member] | Carrying Amount [Member]
Additional disclosures:
Guarantees	$ 0

[1] Net commodity derivative assets and liabilities exclude $120 million of net cash collateral in Level 1.

[2] Net commodity derivative assets and liabilities exclude $202 million of net cash collateral in Level 1.