Debt and Financing Arrangements (Details) (USD $)	Sep. 30, 2014
Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,500,000,000
Commercial paper	265,000,000
$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
$2.5 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	2,000,000,000
$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