Segment Disclosures (Tables)

12 Months Ended

Dec. 31, 2016

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:
	2016	$	7,425	$	74	$	7,499
	2015	7,247		113		7,360
	2014	7,229		408		7,637
Long-lived assets:
	2016	$	38,091	$	—	$	38,091
	2015	38,016		1,580		39,596
	2014	38,290		1,364		39,654

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		Williams NGL & Petchem Services			Other		Eliminations			Total
	(Millions)
2016
Segment revenues:
Service revenues
External	$	5,140	$	2		$	29	$	—		$	5,171
Internal	33		—			19		(52		)	—
Total service revenues	5,173		2			48		(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	$	28		$	48	$	(68	)	$	7,499
Other financial information:
Additions to long-lived assets	$	2,102	$	33		$	11	$	(1	)	$	2,145
Proportional Modified EBITDA of equity-method investments	754		—			—		—			754
2015
Segment revenues:
Service revenues
External	$	5,134	$	2		$	28	$	—		$	5,164
Internal	1		—			158		(159		)	—
Total service revenues	5,135		2			186		(159		)	5,164
Product sales
External	2,196		—			—		—			2,196
Internal	—		—			—		—			—
Total product sales	2,196		—			—		—			2,196
Total revenues	$	7,331	$	2		$	186	$	(159	)	$	7,360
Other financial information:
Additions to long-lived assets	$	2,960	$	360		$	28	$	(12	)	$	3,336
Proportional Modified EBITDA of equity-method investments	699		—			—		—			699
2014
Segment revenues:
Service revenues
External	$	3,887	$	—		$	229	$	—		$	4,116
Internal	1		—			30		(31		)	—
Total service revenues	3,888		—			259		(31		)	4,116
Product sales
External	3,521		—			—		—			3,521
Internal	—		—			—		—			—
Total product sales	3,521		—			—		—			3,521
Total revenues	$	7,409	$	—		$	259	$	(31	)	$	7,637
Other financial information:
Additions to long-lived assets (1)	$	20,413	$	291		$	54	$	(2	)	$	20,756
Proportional Modified EBITDA of equity-method investments	431		(78		)	85		—			438

_______________

(1) 2014 Additions to long-lived assets within our Williams Partners segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition. (See Note 2 - Acquisitions.)

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,
	2016			2015			2014
	(Millions)
Modified EBITDA by segment:
Williams Partners	$	3,864		$	4,003		$	3,244
Williams NGL & Petchem Services	(540		)	(83		)	(115		)
Other	(2		)	(29		)	103
	3,322			3,891			3,232
Accretion expense associated with asset retirement obligations for nonregulated operations	(31		)	(28		)	(18		)
Depreciation and amortization expenses	(1,763		)	(1,738		)	(1,176		)
Impairment of goodwill	—			(1,098		)	—
Equity earnings (losses)	397			335			144
Gain on remeasurement of equity-method investment	—			—			2,544
Impairment of equity-method investments	(430		)	(1,359		)	—
Other investing income (loss) – net	63			27			43
Proportional Modified EBITDA of equity-method investments	(754		)	(699		)	(438		)
Interest expense	(1,179		)	(1,044		)	(747		)
(Provision) benefit for income taxes	25			399			(1,249		)
Income (loss) from discontinued operations, net of tax	—			—			4
Net income (loss)	$	(350	)	$	(1,314	)	$	2,339

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, 2016			December 31, 2015			December 31, 2016		December 31, 2015
	(Millions)
Williams Partners	$	46,265		$	47,870		$	6,701	$	7,336
Williams NGL & Petchem Services	249			835			—		—
Other	674			850			—		—
Eliminations	(353		)	(535		)	—		—
Total	$	46,835		$	49,020		$	6,701	$	7,336