Asset Sales, Impairments and Other Accruals (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Component of Other Expense, Nonoperating [Line Items]
Early debt retirement costs	$ 271	$ 606	$ 1
Other transaction costs		45
Other income (expense) - net	(11)	12	(2)
Costs And Operating Expenses	5,550	4,712	3,712
Midstream Canada & Olefins [Member] | Gulf Liquids [Member]
Component of Other Expense, Nonoperating [Line Items]
Gulf Liquids interest expense reversal associated wtih litigation contingency acrual reversal	14
Charges Related To Leak At Underground Natural Gas Storage Facility [Member] | Williams Partners [Member]
Component of Other Expense, Nonoperating [Line Items]
Costs And Operating Expenses	15	5
Accelerated Amortization Of Debt Costs [Member]
Component of Other Expense, Nonoperating [Line Items]
Other income (expense) - net		4
Noncontrolling Interests
Component of Other Expense, Nonoperating [Line Items]
Other transaction costs		$ 7