General, Description of Business, and Basis of Presentation Assets and Liabilities Held For Sale (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Liabilities	$ 43	$ 0
Williams Olefins, L.L.C. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Other Assets, Current	71
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	901
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	27
Disposal Group, Including Discontinued Operation, Assets	999
Disposal Group, Including Discontinued Operation, Other Liabilities, Current	42
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	1
Disposal Group, Including Discontinued Operation, Liabilities	43
Williams Partners [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets Held-for-sale, Not Part of Disposal Group	$ 24