Debt Leases and Banking Arrangements (Details 1) (USD $) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Commercial Paper [Member] Williams Partners L. P. [Member]	Sep. 30, 2013 $ 900 million unsecured credit facility terminated July 31, 2013 [Member]	Sep. 30, 2013 $2.4 billion WPZ unsecured credit facility terminated July 31, 2013 [Member] Williams Partners L. P. [Member]	Sep. 30, 2013 $2.5 billion WPZ unsecured credit facility [Member] Williams Partners L. P. [Member]	Sep. 30, 2013 $2.5 billion WPZ unsecured credit facility [Member] Transcontinental Gas Pipe Line Company, LLC [Member]	Sep. 30, 2013 $2.5 billion WPZ unsecured credit facility [Member] Northwest Pipeline LLC [Member]	Sep. 30, 2013 $2.5 billion WPZ unsecured credit facility [Member] Letter of Credit [Member] Williams Partners L. P. [Member]	Sep. 30, 2013 $1.5 billion unsecured credit facility [Member]	Sep. 30, 2013 $1.5 billion unsecured credit facility [Member] Bilateral bank agreements for letters of credit [Member]	Sep. 30, 2013 $1.5 billion unsecured credit facility [Member] Letter of Credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity			$ 2,000	$ 900	$ 2,400	$ 2,500	$ 500	$ 500	$ 1,300	$ 1,500		$ 700
Credit facility, loans outstanding						0				0
Credit facility, letters of credit outstanding									0		17	0
Commercial paper, outstanding	371	0	371
Commercial paper, maximum maturity			397 days
Commercial paper, weighted average interest rate			0.41%
Additional amount by which credit facility can be increased						$ 500				$ 500