Fair Value Measurements and Guarantees Recurring Measurements and Additional (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2024	Mar. 31, 2024		Dec. 31, 2023
Additional disclosures:
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Other Assets, Noncurrent
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Other Liabilities and Deferred Revenue, Noncurrent
Derivative, Notional Amount				$ 1,150
Derivative Notional Amount Terminated	$ 750
Derivative, Additional Notional Amount		$ 100
Carrying Amount [Member]
Additional disclosures:
Long-term debt, including current portion		(26,887)		(25,713)
Guarantees		(37)		(37)
Fair Value [Member]
Additional disclosures:
Long-term debt, including current portion		(26,520)		(25,553)
Guarantees		(29)		(28)
Level 1 [Member]
Additional disclosures:
Long-term debt, including current portion		0		0
Guarantees		0		0
Collateral Already Posted, Aggregate Fair Value		70		2
Level 2 [Member]
Additional disclosures:
Long-term debt, including current portion		(26,520)		(25,553)
Guarantees		(13)		(12)
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		282		269
Derivative Asset, Fair Value, Gross Asset		160		310
Derivative Liability, Fair Value, Gross Liability		(232)		(285)
Interest Rate Derivatives, at Fair Value, Net		(4)		6
Fair Value, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis
ARO Trust investments		282		269
Derivative Asset, Fair Value, Gross Asset		160		310
Derivative Liability, Fair Value, Gross Liability		(232)		(285)
Interest Rate Derivatives, at Fair Value, Net		(4)		6
Fair Value, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis
ARO Trust investments		282		269
Derivative Asset, Fair Value, Gross Asset		42	[1]	141	[2]
Derivative Liability, Fair Value, Gross Liability		0	[1]	(3)	[2]
Interest Rate Derivatives, at Fair Value, 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		68		112
Derivative Liability, Fair Value, Gross Liability		(228)		(278)
Interest Rate Derivatives, at Fair Value, Net		(4)		6
Fair Value, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis
ARO Trust investments		0		0
Derivative Asset, Fair Value, Gross Asset		50		57
Derivative Liability, Fair Value, Gross Liability		(4)		(4)
Interest Rate Derivatives, at Fair Value, Net		0		$ 0
Wiltel Guarantee [Member]
Additional disclosures:
Guarantor Obligations, Maximum Exposure, Undiscounted		23
Indemnification Agreement [Member] | Carrying Amount [Member]
Additional disclosures:
Guarantees		$ 0

[1] Commodity derivative assets and liabilities exclude $70 million of net cash collateral in Level 1.

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