Debt and Financing Arrangement (Details)	Mar. 31, 2016 USD ($)
Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,500,000,000
Commercial paper, outstanding	135,000,000
$3.5 billion credit facility [Member]
Line of Credit Facility [Line Items]
Additional Amount By Which Credit Facility Can Be Increased	500,000,000
$3.5 billion credit facility [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount	0
Line of credit facility, amount outstanding	625,000,000
$3.5 billion credit facility [Member] | Williams Partners L.P. [Member] | Commercial paper [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	3,000,000,000
$3.5 billion credit facility [Member] | Letter of credit | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,125,000,000