Divestiture (Details) - Canadian Operations [Member] - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Impairment Of Long Lived Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Williams Partners [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down	[1]		$ 341
Impairment Of Long Lived Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Williams NGL & Petchem Services [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down	[1]		406
Disposal Group, Not Discontinued Operations [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Consideration		$ 1,020			$ 1,020
Divested cash of disposal group		31			31
Reduction in incentive distribution rights payment					150
Income (Loss) from Individually Significant Component Disposed of Attributable to Parent, before Income Tax [Abstract]
Income (loss) before income taxes of disposal group		(9)		$ 6	(98)	$ 13
Income (loss) before income taxes of disposal group attributable to the Williams Companies, Inc.		(16)		6	(95)	11
Disposal Group, Not Discontinued Operations [Member] | Other (income) expense - net [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Loss on sale of Canadian operations		65
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments		15
Disposal Group, Not Discontinued Operations [Member] | Other (income) expense - net [Member] | Williams Partners [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Loss on sale of Canadian operations		32		0	32	0
Disposal Group, Not Discontinued Operations [Member] | Other (income) expense - net [Member] | Williams NGL & Petchem Services [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Loss on sale of Canadian operations		33		$ 0	33	$ 0
Disposal Group, Not Discontinued Operations [Member] | Impairment Of Long Lived Assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down			$ 747
Disposal Group, Not Discontinued Operations [Member] | Cash Consideration [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Consideration		712			712
Disposal Group, Not Discontinued Operations [Member] | Escrow Consideration [Member] | Other Current Assets [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Consideration		243			243
Disposal Group, Not Discontinued Operations [Member] | Other Consideration [Member] | Other Current Assets [Member]
Income Statement and Additional Disclosures by Disposal Groups [Line Items]
Disposal Group, Consideration		$ 81			$ 81

[1] Relates to our Canadian operations. We designated these operations as held for sale as of June 30, 2016. As a result, we measured the fair value of the disposal group, resulting in an impairment charge. The estimated fair value was determined by a market approach based primarily on inputs received in the marketing process and reflects our estimate of the potential assumed proceeds. We disposed of our Canadian operations through a sale during the third quarter of 2016. See Note 2 – Divestiture.