Property, Plant, and Equipment (Details ARO) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024		Dec. 31, 2023
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligation, Liabilities Incurred		$ 474	[1]	$ 42
Regulatory Assets		666		622
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year		2,084		1,914
Liabilities incurred (1)		474	[1]	42
Liabilities settled		(68)		(43)
Accretion		118		97
Revisions (2)	[2]	31		74
Balance at end of year		2,639		2,084
Transcontinental Gas Pipe Line Company, LLC [Member]
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligations, Noncurrent		593		524
Asset Retirement Obligation, Liabilities Incurred		0		8
Regulatory Assets		394		386
Regulatory Liabilities, Noncurrent		976		956
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year		619		563
Liabilities incurred (1)		0		8
Liabilities settled		(32)		(23)
Accretion		29		31
Revisions (2)	[3]	(1)		40
Balance at end of year		615		619
Transcontinental Gas Pipe Line Company, LLC [Member] | Removal Costs
Unusual or Infrequent Item [Line Items]
Regulatory Liabilities, Noncurrent		632		605
Northwest Pipeline LLC [Member]
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligations, Noncurrent		144		136
Regulatory Assets		55		38
Regulatory Liabilities, Noncurrent		233		252
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year		136		129
Accretion		8		7
Balance at end of year		144		136
Northwest Pipeline LLC [Member] | Removal Costs
Unusual or Infrequent Item [Line Items]
Regulatory Liabilities, Noncurrent		30		31
Northwest Pipeline LLC [Member] | Asset Retirement Obligation Costs [Member]
Unusual or Infrequent Item [Line Items]
Regulatory Assets		124		116
Discovery Acquisition
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligation, Liabilities Incurred		250
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Liabilities incurred (1)		250
Gulf Coast Storage Acquisition
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligation, Liabilities Incurred		106
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Liabilities incurred (1)		106
Crowheart Acquisition
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligation, Liabilities Incurred		114
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Liabilities incurred (1)		114
Regulatory liabilities, deferred income, and other [Member]
Unusual or Infrequent Item [Line Items]
Asset Retirement Obligations, Noncurrent		2,548		1,978
Regulatory Liabilities, Noncurrent		$ 1,300		$ 1,288

[1] Includes $250 million, $106 million, and $114 million of ARO in 2024 related to the Discovery, Gulf Coast Storage, and Crowheart Acquisitions, respectively.

[2] Several factors are considered in the annual review process, including inflation rates, current estimates for removal cost, market risk premiums, discount rates, and the estimated remaining useful life of the assets.

[3] Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rate, current estimates for removal costs, discount rates, and the estimated remaining life of assets.