Segment Disclosures (Tables)

3 Months Ended

Mar. 31, 2015

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		Williams NGL & Petchem Services (1)		Other		Eliminations			Total
	(Millions)
Three months ended March 31, 2015
Segment revenues:
Service revenues
External	$	1,192	$	—	$	5	$	—		$	1,197
Internal	—		—		21		(21		)	—
Total service revenues	1,192		—		26		(21		)	1,197
Product sales
External	519		—		—		—			519
Internal	—		—		—		—			—
Total product sales	519		—		—		—			519
Total revenues	$	1,711	$	—	$	26	$	(21	)	$	1,716
Three months ended March 31, 2014
Segment revenues:
Service revenues
External	$	763	$	—	$	56	$	—		$	819
Internal	—		—		3		(3		)	—
Total service revenues	763		—		59		(3		)	819
Product sales
External	930		—		—		—			930
Internal	—		—		—		—			—
Total product sales	930		—		—		—			930
Total revenues	$	1,693	$	—	$	59	$	(3	)	$	1,749
March 31, 2015
Total assets	$	49,284	$	656	$	1,101	$	(584	)	$	50,457
December 31, 2014
Total assets	$	49,322	$	612	$	1,220	$	(591	)	$	50,563

Reconciliation of Modified EBITDA to Segment to Consolidated [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,
	2015			2014
	(Millions)
Modified EBITDA by Segment:
Williams Partners	$	817		$	708
Williams NGL & Petchem Services	(5		)	(100		)
Other	—			58
	812			666
Accretion expense associated with asset retirement obligations for nonregulated operations	(6		)	(3		)
Depreciation and amortization expenses	(427		)	(214		)
Equity earnings (losses)	51			(48		)
Other investing income (loss) – net	—			14
Proportional Modified EBITDA of equity-method investments	(136		)	(28		)
Interest expense	(251		)	(140		)
(Provision) benefit for income taxes	(30		)	(51		)
Net income (loss)	$	13		$	196