Long-Term Debt Issuances and Retirements (Details) - USD ($) $ in Millions	Aug. 17, 2020	Mar. 15, 2020	Jan. 15, 2020	Jul. 15, 2019	Dec. 31, 2020	May 14, 2020	May 08, 2020	Dec. 31, 2019
The Williams Companies, Inc. [Member] | 4.125% Senior Unsecured Notes Due 2020 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 600
Long-term debt interest rate	4.125%				4.125%
Long-term debt					$ 0			$ 600
The Williams Companies, Inc. [Member] | 3.5 Percent Senior Unsecured Notes Due 2030 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate					3.50%	3.50%
Long-term debt face amount						$ 1,000
Long-term debt					$ 1,000			0
The Williams Companies, Inc. [Member] | 5.25% Senior Unsecured Notes Due 2020 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount		$ 1,500
Long-term debt interest rate		5.25%			5.25%
Long-term debt					$ 0			1,500
The Williams Companies, Inc. [Member] | 8.75 Percent Senior Unsecured Notes Due 2020 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount			$ 14
Long-term debt interest rate			8.75%
The Williams Companies, Inc. [Member] | 7.625% Senior Unsecured Notes Due 2019 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount				$ 32
Long-term debt interest rate				7.625%
Transcontinental Gas Pipe Line Company, LLC [Member] | 3.25 Percent Senior Unsecured Notes Due 2030 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate					3.25%		3.25%
Long-term debt face amount							$ 700
Long-term debt					$ 700			0
Transcontinental Gas Pipe Line Company, LLC [Member] | 3.95 Percent Senior Unsecured Notes Due 2050 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate					3.95%		3.95%
Long-term debt face amount							$ 500
Long-term debt					$ 500			$ 0