Fair Value Measurements and Guarantees Recurring Measurements and Additional (Details) - USD ($) $ in Millions		Jun. 30, 2025	Dec. 31, 2024
Energy Related Derivative
Measured on a recurring basis
Derivative Asset		$ 265	$ 344
Derivative Liability		(336)	(400)
Carrying Amount [Member]
Additional disclosures:
Guarantees		(35)	(36)
Long-term debt, including current portion		(28,572)	(26,456)
Carrying Amount [Member] | Gulf Coast Storage Acquisition
Additional disclosures:
Long-term debt, including current portion			(100)
Carrying Amount [Member] | Williams Companies Inc [Member]
Additional disclosures:
Long-term debt, including current portion		(22,394)	(20,167)
Carrying Amount [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(5,221)	(5,235)
Carrying Amount [Member] | Northwest Pipeline LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(583)	(582)
Carrying Amount [Member] | MountainWest [Member]
Additional disclosures:
Long-term debt, including current portion		(374)	(372)
Fair Value [Member]
Additional disclosures:
Guarantees		(28)	(28)
Long-term debt, including current portion		(28,147)	(25,830)
Fair Value [Member] | Gulf Coast Storage Acquisition
Additional disclosures:
Long-term debt, including current portion			(100)
Fair Value [Member] | Williams Companies Inc [Member]
Additional disclosures:
Long-term debt, including current portion		(21,941)	(19,517)
Fair Value [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(5,254)	(5,276)
Fair Value [Member] | Northwest Pipeline LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(579)	(573)
Fair Value [Member] | MountainWest [Member]
Additional disclosures:
Long-term debt, including current portion		(373)	(364)
Level 1 [Member]
Additional disclosures:
Guarantees		0	0
Long-term debt, including current portion		0	0
Level 1 [Member] | Gulf Coast Storage Acquisition
Additional disclosures:
Long-term debt, including current portion			0
Level 1 [Member] | Williams Companies Inc [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 1 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 1 [Member] | Northwest Pipeline LLC [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 1 [Member] | MountainWest [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 2 [Member]
Additional disclosures:
Guarantees		(12)	(12)
Long-term debt, including current portion		(28,147)	(25,830)
Level 2 [Member] | Gulf Coast Storage Acquisition
Additional disclosures:
Long-term debt, including current portion			(100)
Level 2 [Member] | Williams Companies Inc [Member]
Additional disclosures:
Long-term debt, including current portion		(21,941)	(19,517)
Level 2 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(5,254)	(5,276)
Level 2 [Member] | Northwest Pipeline LLC [Member]
Additional disclosures:
Long-term debt, including current portion		(579)	(573)
Level 2 [Member] | MountainWest [Member]
Additional disclosures:
Long-term debt, including current portion		(373)	(364)
Level 3 [Member]
Additional disclosures:
Guarantees		(16)	(16)
Long-term debt, including current portion		0	0
Level 3 [Member] | Gulf Coast Storage Acquisition
Additional disclosures:
Long-term debt, including current portion			0
Level 3 [Member] | Williams Companies Inc [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 3 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 3 [Member] | Northwest Pipeline LLC [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Level 3 [Member] | MountainWest [Member]
Additional disclosures:
Long-term debt, including current portion		0	0
Fair Value, Recurring [Member] | Carrying Amount [Member] | Energy Related Derivative
Measured on a recurring basis
Derivative Asset	[1]	265	344
Derivative Liability	[1]	(336)	(400)
Fair Value, Recurring [Member] | Carrying Amount [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Measured on a recurring basis
ARO Trust investments		323	297
Fair Value, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis
Derivative Asset, Fair Value, Gross Asset		609	726
Derivative Liability, Fair Value, Gross Liability		(949)	(1,070)
Fair Value, Recurring [Member] | Fair Value [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Measured on a recurring basis
ARO Trust investments		323	297
Fair Value, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis
Derivative Asset, Fair Value, Gross Asset		421	427
Derivative Liability, Fair Value, Gross Liability		(522)	(532)
Fair Value, Recurring [Member] | Level 1 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Measured on a recurring basis
ARO Trust investments		323	297
Fair Value, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis
Derivative Asset, Fair Value, Gross Asset		136	188
Derivative Liability, Fair Value, Gross Liability		(380)	(475)
Fair Value, Recurring [Member] | Level 2 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Measured on a recurring basis
ARO Trust investments		0	0
Fair Value, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis
Derivative Asset, Fair Value, Gross Asset		52	111
Derivative Liability, Fair Value, Gross Liability		(47)	(63)
Fair Value, Recurring [Member] | Level 3 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Measured on a recurring basis
ARO Trust investments		0	$ 0
Wiltel Guarantee [Member]
Additional disclosures:
Guarantor Obligations, Maximum Exposure, Undiscounted		21
Indemnification Agreement [Member] | Carrying Amount [Member]
Additional disclosures:
Guarantees		$ 0

[1] The carrying amount is presented net of counterparty offsetting arrangements and collateral (see Note 9 – Commodity Derivatives)