Debt and Financing Arrangements (Details Textual) (USD $)	Jun. 30, 2013 Williams Partners L.P. [Member]	Jun. 30, 2013 $2.4 billion credit facility [Member]	Jun. 30, 2013 $2.4 billion credit facility [Member] Williams Partners L.P. [Member]	Jun. 30, 2013 $2.4 billion credit facility [Member] Williams Partners L.P. [Member] LetterOfCreditMember	Jul. 31, 2013 $2.5 billion credit facility [Member]	Jul. 31, 2013 $2.5 billion credit facility [Member] Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 400,000,000	$ 2,400,000,000	$ 1,300,000,000	$ 500,000,000	$ 2,500,000,000
Letters of Credit Outstanding, Amount				0
Line of Credit Facility, Amount Outstanding			0
Additional Amount By Which Credit Facility Can Be Increased						500,000,000
Commercial Paper	$ 710,000,000