Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Assets	$ 46,049	$ 47,612
Variable Interest Entity, Primary Beneficiary [Member] | Cash and cash equivalents [Member]
Variable Interest Entity [Line Items]
Assets	116	78
Variable Interest Entity, Primary Beneficiary [Member] | Trade accounts and other receivables - net [Member]
Variable Interest Entity [Line Items]
Assets	104	132
Variable Interest Entity, Primary Beneficiary [Member] | Inventories [Member]
Variable Interest Entity [Line Items]
Assets	3	3
Variable Interest Entity, Primary Beneficiary [Member] | Other current assets and deferred charges [Member]
Variable Interest Entity [Line Items]
Assets	4	7
Variable Interest Entity, Primary Beneficiary [Member] | Property, plant, and equipment - net [Member]
Variable Interest Entity [Line Items]
Assets	5,237	5,295
Variable Interest Entity, Primary Beneficiary [Member] | Intangible assets - net of accumulated amortization [Member]
Variable Interest Entity [Line Items]
Assets	2,240	2,267
Variable Interest Entity, Primary Beneficiary [Member] | Regulatory assets, deferred charges, and other [Member]
Variable Interest Entity [Line Items]
Assets	23	20
Variable Interest Entity, Primary Beneficiary [Member] | Accounts payable [Member]
Variable Interest Entity [Line Items]
Liabilities	(50)	(61)
Variable Interest Entity, Primary Beneficiary [Member] | Accrued liabilities [Member]
Variable Interest Entity [Line Items]
Liabilities	(32)	(29)
Variable Interest Entity, Primary Beneficiary [Member] | Regulatory liabilities, deferred income, and other [Member]
Variable Interest Entity [Line Items]
Liabilities	$ (286)	$ (287)
Variable Interest Entity, Primary Beneficiary [Member] | Williams Companies Inc [Member] | Northeast JV [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	65.00%
Variable Interest Entity, Primary Beneficiary [Member] | Williams Companies Inc [Member] | Gulfstar One [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	51.00%
Variable Interest Entity, Primary Beneficiary [Member] | Williams Companies Inc [Member] | Cardinal Gas Services LLC [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	66.00%
Variable Interest Entity, Not Primary Beneficiary [Member] | Williams Companies Inc [Member] | Targa Train 7 LLC
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	20.00%
Equity Method Investments	$ 47