Segment Disclosures (Tables)

3 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Reconciliation of Revenue from Segments to Consolidated [Table Text Block]

The following table reflects the reconciliation of Segment revenues to Total revenues as reported in the Consolidated Statement of Income and Total assets by reportable segment.

	Williams Partners		Other		Eliminations			Total
	(Millions)
Three Months Ended March 31, 2018
Segment revenues:
Service revenues
External	$	1,346	$	5	$	—		$	1,351
Internal	—		3		(3		)	—
Total service revenues	1,346		8		(3		)	1,351
Total service revenues – commodity consideration (external only)	101		—		—			101
Product sales
External	636		—		—			636
Internal	—		—		—			—
Total product sales	636		—		—			636
Total revenues	$	2,083	$	8	$	(3	)	$	2,088
Three Months Ended March 31, 2017
Segment revenues:
Service revenues
External	$	1,256	$	5	$	—		$	1,261
Internal	—		3		(3		)	—
Total service revenues	1,256		8		(3		)	1,261
Product sales
External	727		—		—			727
Internal	—		—		—			—
Total product sales	727		—		—			727
Total revenues	$	1,983	$	8	$	(3	)	$	1,988
March 31, 2018
Total assets	$	46,575	$	541	$	(64	)	$	47,052
December 31, 2017
Total assets	$	45,903	$	589	$	(140	)	$	46,352

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 Income.

	Three Months Ended   March 31,
	2018			2017
	(Millions)
Modified EBITDA by segment:
Williams Partners	$	1,107		$	1,132
Other	13			18
	1,120			1,150
Accretion expense associated with asset retirement obligations for nonregulated operations	(8		)	(7		)
Depreciation and amortization expenses	(431		)	(442		)
Equity earnings (losses)	82			107
Other investing income (loss) – net	4			272
Proportional Modified EBITDA of equity-method investments	(169		)	(194		)
Interest expense	(273		)	(280		)
(Provision) benefit for income taxes	(55		)	(37		)
Net income (loss)	$	270		$	569