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Other Income and Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		28 Months Ended
Other Income and Expenses (Details) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015
Segment Reporting Information [Line Items]
Gain on Extinguishment of Debt			$ 14
Williams Partners [Member]
Segment Reporting Information [Line Items]
Amortization of regulatory asset associated with ARO	$ 8	$ 8	25	$ 25
Impairment of certain assets	2	0	29	17
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	21	10	57	20
Net gain related to partial acreage dedication release	0	(12)	0	(12)
Acquisition and Merger [Member] \| Interest incurred [Member]
Segment Reporting Information [Line Items]
Business Combination, Acquisition Related Costs			2	9
Acquisition and Merger [Member] \| Williams Partners [Member] \| Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Business Combination, Acquisition Related Costs		17	26	19
Transition [Member] \| Williams Partners [Member] \| Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs	1	4	9	4
Transition [Member] \| Williams Partners [Member] \| Operation and maintenance [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs		3	10	3
Other Restructuring [Member] \| Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Strategic Alternative, Related Cost	18		25
Business Combination, Integration Related Costs	7	$ 3	20	3
Bluegrass Pipeline Company Llc [Member] \| Williams NGL & Petchem Services [Member]
Segment Reporting Information [Line Items]
Project Development Costs				19
Geismar Incident [Member] \| Williams Partners [Member]
Segment Reporting Information [Line Items]
Insurance recoveries			126	175
Insurable Expenses in Excess of our Deductibles				$ 14
Insurance Claims [Member] \| Geismar Incident [Member] \| Property Damage And Business Interruption [Member] \| Williams Partners [Member]
Segment Reporting Information [Line Items]
Maximum insurance recoverable amount	$ 480		$ 480		$ 480
Insurance recoveries					$ 422