Debt and Financing Arrangements (Details Textual) (USD $)	Sep. 30, 2013	Jul. 31, 2013
Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Commercial Paper	$ 371,000,000
$2.4 billion credit facility [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,400,000,000
$2.5 billion credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		500,000,000
Letters of Credit Outstanding, Amount	0
Line of Credit Facility, Amount Outstanding	0
Line of Credit Facility, Remaining Borrowing Capacity	500,000,000
$2.5 billion credit facility [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,500,000,000
Additional amount credit facility can be increased		500,000,000
$2.5 billion credit facility [Member] | Williams Partners L.P. [Member] | Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,300,000,000