Debt Leases and Banking Arrangements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Aug. 31, 2011 $375 million (5.4%) due 2041 Unsecured Debt [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $375 million (5.4%) due 2041 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $375 million (5.4%) due 2041 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Jul. 31, 2012 $325 million (8.875%) due 2012 Unsecured Debt [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $325 million (8.875%) due 2012 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $325 million (8.875%) due 2012 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $200 million (6.4%) due 2016 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $200 million (6.4%) due 2016 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $250 million (6.05%) due 2018 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $250 million (6.05%) due 2018 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $8 million (7.08%) due 2026 Unsecured Debt [Member] Debentures [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $8 million (7.08%) due 2026 Unsecured Debt [Member] Debentures [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $200 million (7.25%) due 2026 Unsecured Debt [Member] Debentures [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $200 million (7.25%) due 2026 Unsecured Debt [Member] Debentures [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $175 million (7%) due 2016 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2011 $175 million (7%) due 2016 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2012 $185 million (5.95%) due 2017 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2011 $185 million (5.95%) due 2017 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2012 $250 million (6.05%) due 2018 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2011 $250 million (6.05%) due 2018 Unsecured Debt [Member] Senior Notes [Member] Northwest Pipeline GP [Member]	Dec. 31, 2012 $85 million (7.125%) due 2025 Unsecured Debt [Member] Debentures [Member] Northwest Pipeline GP [Member]	Dec. 31, 2011 $85 million (7.125%) due 2025 Unsecured Debt [Member] Debentures [Member] Northwest Pipeline GP [Member]	Dec. 31, 2012 $750 million (3.8%) due 2015 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $750 million (3.8%) due 2015 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $600 million (7.25%) due 2017 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $600 million (7.25%) due 2017 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $1.5 billion (5.25%) due 2020 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $1.5 billion (5.25%) due 2020 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $600 million (4.125%) due 2020 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $600 million (4.125%) due 2020 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $500 million (4%) due 2021 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $500 million (4%) due 2021 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $1.25 billion (6.3%) due 2040 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $1.25 billion (6.3%) due 2040 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $750 million (7.875%) due 2021 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2011 $750 million (7.875%) due 2021 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2012 $700 million (7.5%) due 2031 Unsecured Debt [Member] Debentures [Member] The Williams Companies, Inc.	Dec. 31, 2011 $700 million (7.5%) due 2031 Unsecured Debt [Member] Debentures [Member] The Williams Companies, Inc.	Dec. 31, 2012 $480 million (7.75%) due 2031 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2011 $480 million (7.75%) due 2031 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2012 $850 million (8.75%) due 2032 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2011 $850 million (8.75%) due 2032 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2012 Various (5.5% to 10.25%) due 2019 to 2033 Unsecured Debt [Member] Senior Notes And Debentures [Member] The Williams Companies, Inc.	Dec. 31, 2011 Various (5.5% to 10.25%) due 2019 to 2033 Unsecured Debt [Member] Senior Notes And Debentures [Member] The Williams Companies, Inc.	Dec. 31, 2012 Various (5.5% to 10.25%) due 2019 to 2033 Unsecured Debt [Member] Senior Notes And Debentures [Member] The Williams Companies, Inc. Minimum [Member]	Dec. 31, 2012 Various (5.5% to 10.25%) due 2019 to 2033 Unsecured Debt [Member] Senior Notes And Debentures [Member] The Williams Companies, Inc. Maximum [Member]	Dec. 31, 2012 Other	Dec. 31, 2011 Other	Dec. 31, 2012 $400 million (4.45%) due 2042 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Jul. 31, 2012 $400 million (4.45%) due 2042 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2011 $400 million (4.45%) due 2042 Unsecured Debt [Member] Senior Notes [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Dec. 31, 2012 $750 million (3.35%) due 2022 Unsecured Debt [Member] Williams Partners L. P. [Member]	Dec. 31, 2011 $750 million (3.35%) due 2022 Unsecured Debt [Member] Williams Partners L. P. [Member]	Aug. 31, 2012 $750 million (3.35%) due 2022 Unsecured Debt [Member] Senior Notes [Member] Williams Partners L. P. [Member]	Dec. 31, 2012 $850 million (3.7%) due 2023 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.	Dec. 31, 2011 $850 million (3.7%) due 2023 Unsecured Debt [Member] Senior Notes [Member] The Williams Companies, Inc.
Long-term Debt
Debt Instrument, Interest Rate, Stated Percentage			5.40%	5.40%		8.875%	8.875%		6.40%		6.05%		7.08%		7.25%		7.00%		5.95%		6.05%		7.125%		3.80%		7.25%		5.25%		4.125%		4.00%		6.30%		7.875%		7.50%		7.75%		8.75%				5.50%	10.25%			4.45%	4.45%		3.35%		3.35%	3.70%
Debt Instrument, Principal Outstanding				$ 375	$ 375		$ 0	$ 325	$ 200	$ 200	$ 250	$ 250	$ 8	$ 8	$ 200	$ 200	$ 175	$ 175	$ 185	$ 185	$ 250	$ 250	$ 85	$ 85	$ 750	$ 750	$ 600	$ 600	$ 1,500	$ 1,500	$ 600	$ 600	$ 500	$ 500	$ 1,250	$ 1,250	$ 371	$ 371	$ 339	$ 339	$ 252	$ 252	$ 445	$ 445	$ 57	$ 90					$ 400		$ 0	$ 750	$ 0		$ 850	$ 0
Other, including secured capital lease obligations																																																	2	4
Net Unamortized debt discount	(33)	(32)
Total Long-term debt, including current portion	10,736	8,722
Long-term debt due within one year	(1)	(353)
Long-term debt	$ 10,735	$ 8,369