Credit Facilities and Commercial Paper (Details) $ in Millions					12 Months Ended
		Dec. 18, 2015	Aug. 26, 2015 USD ($)	Feb. 02, 2015 USD ($)	Dec. 31, 2015 USD ($)		Feb. 25, 2016 USD ($)	Dec. 23, 2015 USD ($)	Mar. 03, 2015 USD ($)	Dec. 31, 2014 USD ($)
Credit Facility and Commercial Paper [Line Items]
Commercial paper, outstanding					$ 499					$ 798
Williams Companies, Inc. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 1,500	1,500
Credit facility, loans outstanding					650					370
Additional amount by which credit facility can be increased				$ 500
Maximum ratio of debt to EBITDA				5
Maximum ratio of debt to EBITDA after acquisition				5.5
Williams Companies, Inc. [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, loans outstanding							$ 475
Williams Companies, Inc. [Member] | Swingline Loan [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 50
Williams Companies, Inc. [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				675
Williams Companies, Inc. [Member] | Letters Of Credit Under Certain Bilateral Bank Agreements [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, letters of credit outstanding					14
Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				3,500	3,500	[1]
Credit facility, loans outstanding	[1]				1,310
Additional amount by which credit facility can be increased				$ 500
Williams Partners L.P. [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, loans outstanding							$ 925
Williams Partners L.P. [Member] | Rate addition to federal funds effective rate [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate				0.50%
Williams Partners L.P. [Member] | Rate addition to London interbank offered rate (LIBOR) [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate				1.00%
Williams Partners L.P. [Member] | Swingline Loan [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 150
Williams Partners L.P. [Member] | Commercial paper [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				3,000
Commercial paper, outstanding					$ 499					$ 798
Commercial paper, weighted average interest rate					0.92%					0.92%
Commercial paper, maximum maturity					397 days
Williams Partners L.P. [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				1,125
Williams Partners L.P. [Member] | Letters Of Credit Under Certain Bilateral Bank Agreements [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, letters of credit outstanding					$ 2
Williams Partners L.P. [Member] | Short-term facility [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity					150
Credit facility, loans outstanding					0
Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity			$ 3,500
Credit facility, loans outstanding					$ 1,310					$ 640
Maximum ratio of debt to EBITDA			6.0
Williams Partners L.P. [Member] | Short-term facility [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity			$ 1,000					$ 150	$ 1,500
Transcontinental Gas Pipe Line Company, LLC [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 500
Maximum ratio of debt to capitalization				65.00%
Northwest Pipeline LLC [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 500
Maximum ratio of debt to capitalization				65.00%
Acquisition [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.5
Mar 2017 & Subsequent Quarters [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.00
Sep & Dec 2016 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.50
Dec 2015, Mar & Jun 2016 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.75
Variable Interest Term Loan due 2018 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					1.8531%
Long-term debt								$ 850
Variable Interest Term Loan due 2018 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Long-term debt					$ 850					$ 0

[1] In managing our available liquidity, we do not expect a maximum outstanding amount in excess of the capacity of our credit facility inclusive of any outstanding amounts under our commercial paper program.