Fair Value Measurements and Guarantees Recurring Measurements and Additional (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 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	$ 50		$ 1,150
Derivative Notional Amount Terminated	1,750
Derivative, Additional Notional Amount	650
Carrying Amount [Member]
Additional disclosures:
Long-term debt, including current portion	(27,109)		(25,713)
Guarantees	(36)		(37)
Fair Value [Member]
Additional disclosures:
Long-term debt, including current portion	(27,248)		(25,553)
Guarantees	(28)		(28)
Level 1 [Member]
Additional disclosures:
Long-term debt, including current portion	0		0
Guarantees	0		0
Collateral Already Posted, Aggregate Fair Value	76		2
Level 2 [Member]
Additional disclosures:
Long-term debt, including current portion	(27,248)		(25,553)
Guarantees	(12)		(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	295		269
Derivative Asset, Fair Value, Gross Asset	132		310
Derivative Liability, Fair Value, Gross Liability	(319)		(285)
Interest Rate Derivatives, at Fair Value, Net			6
Fair Value, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis
ARO Trust investments	295		269
Derivative Asset, Fair Value, Gross Asset	132		310
Derivative Liability, Fair Value, Gross Liability	(319)		(285)
Interest Rate Derivatives, at Fair Value, Net			6
Fair Value, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis
ARO Trust investments	295		269
Derivative Asset, Fair Value, Gross Asset	21	[1]	141	[2]
Derivative Liability, Fair Value, Gross Liability	0	[1]	(3)	[2]
Interest Rate Derivatives, at Fair Value, Net			0
Fair Value, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis
ARO Trust investments	0		0
Derivative Asset, Fair Value, Gross Asset	62		112
Derivative Liability, Fair Value, Gross Liability	(317)		(278)
Interest Rate Derivatives, at Fair Value, Net			6
Fair Value, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis
ARO Trust investments	0		0
Derivative Asset, Fair Value, Gross Asset	49		57
Derivative Liability, Fair Value, Gross Liability	(2)		(4)
Interest Rate Derivatives, at Fair Value, Net			$ 0
Wiltel Guarantee [Member]
Additional disclosures:
Guarantor Obligations, Maximum Exposure, Undiscounted	22
Indemnification Agreement [Member] | Carrying Amount [Member]
Additional disclosures:
Guarantees	$ 0

[1] Commodity derivative assets and liabilities exclude $76 million of net cash collateral in Level 1.

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