Asset Sales and Other Accruals (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Component of Operating Other Cost and Expense [Line Items]
Other (income) expense - net	$ 24	$ 1	$ (15)
Williams Partners [Member]
Component of Operating Other Cost and Expense [Line Items]
Involuntary conversion gains	0	(3)	(18)
Gains on sales of certain assets	(6)	0	(12)
Williams NGL & Petchem Services [Member] | Gulf Liquids [Member]
Component of Operating Other Cost and Expense [Line Items]
Gulf Liquids litigation contingency accrual reduction	0	(19)	0
Capitalization Of Project Feasibility Costs Previously Expensed [Member] | Williams Partners [Member]
Component of Operating Other Cost and Expense [Line Items]
Other (income) expense - net	(19)	(11)	(1)
Accrual Of Regulatory Liability Related To Overcollection Of Certain Employee Expenses [Member] | Williams Partners [Member]
Component of Operating Other Cost and Expense [Line Items]
Other (income) expense - net	4	9	10
Project Feasibility Costs [Member] | Williams Partners [Member]
Component of Operating Other Cost and Expense [Line Items]
Other (income) expense - net	$ 21	$ 10	$ 8