Debt and Banking Arrangements Long-Term Debt Issuances and Retirements (Details 1) - USD ($) $ in Millions	Mar. 15, 2020	Jan. 15, 2020	May 14, 2020	May 08, 2020
3.5 Percent Senior Unsecured Notes Due 2030 [Member] | Williams Companies Inc [Member]
Debt Instrument [Line Items]
Long-term debt interest rate			3.50%
Debt Instrument, Face Amount			$ 1,000
3.25 Percent Senior Unsecured Notes Due 2030 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Debt Instrument [Line Items]
Long-term debt interest rate				3.25%
Debt Instrument, Face Amount				$ 700
Additional Interest Rate Accrued For Default Of Registration Rights Agreement First Period				0.25%
Additional Interest Rate Accrued For Default Of Registration Rights Agreements Each Subsequent Period				0.25%
Maximum Additional Interest Rate Accrued For Default Of Registration Rights Agreements All Periods				0.50%
3.95 Percent Senior Unsecured Notes Due 2050 [Member] | Transcontinental Gas Pipe Line Company, LLC [Member]
Debt Instrument [Line Items]
Long-term debt interest rate				3.95%
Debt Instrument, Face Amount				$ 500
Additional Interest Rate Accrued For Default Of Registration Rights Agreement First Period				0.25%
Additional Interest Rate Accrued For Default Of Registration Rights Agreements Each Subsequent Period				0.25%
Maximum Additional Interest Rate Accrued For Default Of Registration Rights Agreements All Periods				0.50%
5.25 Percent Senior Unsecured Notes Due 2020 [Member] | Williams Companies Inc [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 1,500
Long-term debt interest rate	5.25%
8.75 Percent Senior Unsecured Notes Due 2020 [Member] | Williams Companies Inc [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount		$ 14
Long-term debt interest rate		8.75%