Long-Term Debt Issuances and Retirements (Details) - USD ($) $ in Millions								3 Months Ended
	Jun. 15, 2018	Mar. 28, 2018	Jul. 06, 2017	Jul. 03, 2017	Apr. 15, 2017	Feb. 23, 2017	Feb. 01, 2017	Dec. 31, 2018	Sep. 30, 2017	Aug. 24, 2018	Mar. 15, 2018	Mar. 05, 2018	Dec. 31, 2017	Jun. 05, 2017	Apr. 03, 2017
6.125% Senior Unsecured Notes due 2022 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount						$ 750
Long-term debt interest rate						6.125%
4.875% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount				$ 1,400
Long-term debt interest rate				4.875%
4.875% Senior Unsecured Notes due 2024 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount		$ 750
Long-term debt interest rate		4.875%
Williams Partners L.P. [Member] | Variable interest Rate [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount			$ 850
Williams Partners L.P. [Member] | 6.125% Senior Unsecured Notes due 2022 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount						$ 750
Long-term debt interest rate						6.125%
Williams Partners L.P. [Member] | 7.25% Senior Unsecured Notes due 2017 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount							$ 600
Long-term debt interest rate							7.25%
Williams Partners L.P. [Member] | 3.75% Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt face amount														$ 1,450
Long-term debt interest rate														3.75%
Williams Partners L.P. [Member] | 4.875% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount				$ 1,400
Long-term debt interest rate				4.875%
Williams Partners L.P. [Member] | 4.85%SeniorUnsecuredNotesDue2048 [Member]
Debt Instrument [Line Items]
Long-term debt face amount												$ 800
Long-term debt interest rate												4.85%
The Williams Companies, Inc. [Member] | 3.9% Senior Unsecured Notes due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								3.90%
The Williams Companies, Inc. [Member] | 4.9% Senior Unsecured Notes due 2045 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.90%
The Williams Companies, Inc. [Member] | 4.55% Senior Unsecured Notes due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.55%
The Williams Companies, Inc. [Member] | 5.75% Senior Unsecured Notes due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								5.75%
The Williams Companies, Inc. [Member] | 4.3% Senior Unsecured Notes Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.30%
The Williams Companies, Inc. [Member] | 5.4% Senior Unsecured Notes Due 2044 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								5.40%
The Williams Companies, Inc. [Member] | 4.5% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.50%
The Williams Companies, Inc. [Member] | 5.8% Senior Unsecured Notes due 2043 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								5.80%
The Williams Companies, Inc. [Member] | 3.6% Senior Unsecured Notes due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								3.60%
The Williams Companies, Inc. [Member] | 4% Senior Unsecured Notes due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.00%
The Williams Companies, Inc. [Member] | 5.1% Senior Unsecured Notes due 2045 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								5.10%
The Williams Companies, Inc. [Member] | 3.75% Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								3.75%
The Williams Companies, Inc. [Member] | 4.85%SeniorUnsecuredNotesDue2048 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								4.85%
The Williams Companies, Inc. [Member] | 4.875% Senior Unsecured Notes due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate													4.875%
Northwest Pipeline LLC [Member] | 4% Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt face amount										$ 250					$ 250
Long-term debt interest rate								4.00%		4.00%					4.00%
Northwest Pipeline LLC [Member] | 5.95% Senior Unsecured Notes due 2017 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount					$ 185
Long-term debt interest rate					5.95%
Northwest Pipeline LLC [Member] | 6.05% Senior Unsecured Notes due 2018 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 250
Long-term debt interest rate	6.05%												6.05%
Transcontinental Gas Pipe Line Company, LLC [Member]
Debt Instrument [Line Items]
Other Long-term Debt, Noncurrent								$ 1,067					$ 231
Transcontinental Gas Pipe Line Company, LLC [Member] | 7.85% Senior Unsecured Notes Due 2026 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate								7.85%
Transcontinental Gas Pipe Line Company, LLC [Member] | 6.05% Senior Unsecured Notes due 2018 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 250
Long-term debt interest rate	6.05%												6.05%
Transcontinental Gas Pipe Line Company, LLC [Member] | 4% Senior Unsecured Notes Due 2028 [Member]
Debt Instrument [Line Items]
Long-term debt face amount											$ 400
Long-term debt interest rate								4.00%			4.00%
Transcontinental Gas Pipe Line Company, LLC [Member] | 4.6%SeniorUnsecuredNotesDue2048 [Member]
Debt Instrument [Line Items]
Long-term debt face amount											$ 600
Long-term debt interest rate								4.60%			4.60%
Transcontinental Gas Pipe Line Company, LLC [Member] | Dalton [Member]
Debt Instrument [Line Items]
Other Long-term Debt, Noncurrent								$ 260					$ 231
Percent Of Construction Costs Capitalized								100.00%
Debt Instrument, Term									35 years
Transcontinental Gas Pipe Line Company, LLC [Member] | AtlanticSunrise [Member]
Debt Instrument [Line Items]
Other Long-term Debt, Noncurrent								$ 807
Percent Of Construction Costs Capitalized								100.00%
Debt Instrument, Term								20 years