Segment Disclosures Reconciliation of Segment Revenues and Assets to Consolidated (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment revenues:
Revenues	$ 1,736	$ 1,839	$ 3,396	$ 3,555
Total assets by reporting segment
Total assets	48,124		48,124		$ 49,020
Service [Member]
Segment revenues:
Revenues	1,202	1,241	2,431	2,438
Product [Member]
Segment revenues:
Revenues	534	598	965	1,117
Williams Partners [Member]
Total assets by reporting segment
Total assets	47,294		47,294		47,870
Williams Partners [Member] | Service [Member]
Segment revenues:
Revenues	1,193	1,231	2,415	2,423
Williams Partners [Member] | Product [Member]
Segment revenues:
Revenues	520	598	948	1,117
Williams NGL & Petchem Services [Member]
Total assets by reporting segment
Total assets	475		475		835
Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Revenues	2	1	2	1
Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Revenues	14	0	17	0
Other [Member]
Total assets by reporting segment
Total assets	822		822		850
Other [Member] | Service [Member]
Segment revenues:
Revenues	7	9	14	14
Other [Member] | Product [Member]
Segment revenues:
Revenues	0	0	0	0
Operating Segments [Member] | Williams Partners [Member]
Segment revenues:
Revenues	1,730	1,830	3,384	3,541
Operating Segments [Member] | Williams Partners [Member] | Service [Member]
Segment revenues:
Revenues	1,210	1,231	2,436	2,423
Operating Segments [Member] | Williams Partners [Member] | Product [Member]
Segment revenues:
Revenues	520	599	948	1,118
Operating Segments [Member] | Williams NGL & Petchem Services [Member]
Segment revenues:
Revenues	16	1	19	1
Operating Segments [Member] | Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Revenues	2	1	2	1
Operating Segments [Member] | Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Revenues	14	0	17	0
Operating Segments [Member] | Other [Member]
Segment revenues:
Revenues	11	47	29	73
Operating Segments [Member] | Other [Member] | Service [Member]
Segment revenues:
Revenues	11	47	29	73
Operating Segments [Member] | Other [Member] | Product [Member]
Segment revenues:
Revenues	0	0	0	0
Intersegment Elimination [Member]
Segment revenues:
Revenues	(21)	(39)	(36)	(60)
Total assets by reporting segment
Total assets	(467)		(467)		$ (535)
Intersegment Elimination [Member] | Service [Member]
Segment revenues:
Revenues	(21)	(38)	(36)	(59)
Intersegment Elimination [Member] | Product [Member]
Segment revenues:
Revenues	0	(1)	0	(1)
Intersegment Elimination [Member] | Williams Partners [Member] | Service [Member]
Segment revenues:
Revenues	(17)	0	(21)	0
Intersegment Elimination [Member] | Williams Partners [Member] | Product [Member]
Segment revenues:
Revenues	0	(1)	0	(1)
Intersegment Elimination [Member] | Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Revenues	0	0	0	0
Intersegment Elimination [Member] | Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Revenues	0	0	0	0
Intersegment Elimination [Member] | Other [Member] | Service [Member]
Segment revenues:
Revenues	(4)	(38)	(15)	(59)
Intersegment Elimination [Member] | Other [Member] | Product [Member]
Segment revenues:
Revenues	$ 0	$ 0	$ 0	$ 0