Segment Disclosures (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]

The following geographic area data includes Revenues from external customers based on product shipment origin and Long-lived assets based upon physical location:

		United States		Canada		Total
		(Millions)
Revenues from external customers:
	2017	$	8,030	$	1	$	8,031
	2016	7,425		74		7,499
	2015	7,247		113		7,360
Long-lived assets:
	2017	$	37,002	$	—	$	37,002
	2016	38,091		—		38,091
	2015	38,016		1,580		39,596

Long-lived assets are comprised of property, plant, and equipment, goodwill, and other intangible assets.

Reconciliation of revenue from segment to consolidated [Table Text Block]

The following table reflects the reconciliation of Segment revenues to Total revenues as reported in the Consolidated Statement of Operations and Other financial information:

	Williams Partners		Other		Eliminations			Total
	(Millions)
2017
Segment revenues:
Service revenues
External	$	5,291	$	21	$	—		$	5,312
Internal	1		11		(12		)	—
Total service revenues	5,292		32		(12		)	5,312
Product sales
External	2,718		1		—			2,719
Internal	—		—		—			—
Total product sales	2,718		1		—			2,719
Total revenues	$	8,010	$	33	$	(12	)	$	8,031
Other financial information:
Additions to long-lived assets	$	2,792	$	22	$	—		$	2,814
Proportional Modified EBITDA of equity-method investments	795		—		—			795
2016
Segment revenues:
Service revenues
External	$	5,140	$	31	$	—		$	5,171
Internal	33		19		(52		)	—
Total service revenues	5,173		50		(52		)	5,171
Product sales
External	2,318		10		—			2,328
Internal	—		16		(16		)	—
Total product sales	2,318		26		(16		)	2,328
Total revenues	$	7,491	$	76	$	(68	)	$	7,499
Other financial information:
Additions to long-lived assets	$	2,102	$	44	$	(1	)	$	2,145
Proportional Modified EBITDA of equity-method investments	754		—		—			754
2015
Segment revenues:
Service revenues
External	$	5,134	$	30	$	—		$	5,164
Internal	1		91		(92		)	—
Total service revenues	5,135		121		(92		)	5,164
Product sales
External	2,196		—		—			2,196
Internal	—		—		—			—
Total product sales	2,196		—		—			2,196
Total revenues	$	7,331	$	121	$	(92	)	$	7,360
Other financial information:
Additions to long-lived assets	$	2,960	$	388	$	(12	)	$	3,336
Proportional Modified EBITDA of equity-method investments	699		—		—			699

Reconciliation of Modified EBITDA to Net income (loss) [Table Text Block]

The following table reflects the reconciliation of Modified EBITDA to Net income (loss) as reported in the Consolidated Statement of Operations:

	Years Ended December 31,
	2017			2016			2015
	(Millions)
Modified EBITDA by segment:
Williams Partners	$	3,616		$	3,864		$	4,003
Other	(150		)	(542		)	(112		)
	3,466			3,322			3,891
Accretion expense associated with asset retirement obligations for nonregulated operations	(33		)	(31		)	(28		)
Depreciation and amortization expenses	(1,736		)	(1,763		)	(1,738		)
Impairment of goodwill	—			—			(1,098		)
Equity earnings (losses)	434			397			335
Impairment of equity-method investments	—			(430		)	(1,359		)
Other investing income (loss) – net	282			63			27
Proportional Modified EBITDA of equity-method investments	(795		)	(754		)	(699		)
Interest expense	(1,083		)	(1,179		)	(1,044		)
(Provision) benefit for income taxes	1,974			25			399
Net income (loss)	$	2,509		$	(350	)	$	(1,314	)

Total assets and equity method investments by reporting segment [Table Text Block]

The following table reflects Total assets and Equity-method investments by reportable segments:

	Total Assets						Equity-Method Investments
	December 31, 2017			December 31, 2016			December 31, 2017		December 31, 2016
	(Millions)
Williams Partners	$	45,903		$	46,265		$	6,552	$	6,701
Other	589			685			—		—
Eliminations	(140		)	(115		)	—		—
Total	$	46,352		$	46,835		$	6,552	$	6,701