Divestitures (Tables)

12 Months Ended

Dec. 31, 2018

Four Corners [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Results of Operations of Disposal Group [Table Text Block]

The following table presents the results of operations for the Four Corners area, excluding the gain noted above:

	Years Ended December 31,
	2018		2017		2016
	(Millions)
Income (loss) before income taxes of Four Corners area	$	52	$	47	$	37
Income (loss) before income taxes of Four Corners area attributable to The Williams Companies, Inc.	43		35		23

Williams Olefins, L.L.C. [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Results of Operations of Disposal Group [Table Text Block]

The following table presents the results of operations for the Geismar Interest, excluding the gain noted above:

	Years Ended December 31,
	2018		2017		2016
	(Millions)
Income (loss) before income taxes of the Geismar Interest	$	—	$	26	$	141
Income (loss) before income taxes of the Geismar Interest attributable to The Williams Companies, Inc.	—		19		85