Segment Disclosures Reconciliation of Segment Revenues to Consolidated (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment revenues
Service revenues	$ 1,282	$ 1,202	$ 2,543	$ 2,431
Product sales	642	534	1,369	965
Total revenues	1,924	1,736	3,912	3,396
Williams Partners [Member]
Segment revenues
Service revenues	1,276	1,193	2,532	2,415
Product sales	642	530	1,369	958
Other [Member]
Segment revenues
Service revenues	6	9	11	16
Product sales	0	4	0	7
Intersegment Elimination [Member]
Segment revenues
Service revenues	(4)	(20)	(7)	(35)
Product sales	0	(10)	0	(10)
Total revenues	(4)	(30)	(7)	(45)
Intersegment Elimination [Member] | Williams Partners [Member]
Segment revenues
Service revenues	(1)	(17)	(1)	(21)
Product sales	0	0	0	0
Intersegment Elimination [Member] | Other [Member]
Segment revenues
Service revenues	(3)	(3)	(6)	(14)
Product sales	0	(10)	0	(10)
Operating Segments [Member] | Williams Partners [Member]
Segment revenues
Service revenues	1,277	1,210	2,533	2,436
Product sales	642	530	1,369	958
Total revenues	1,919	1,740	3,902	3,394
Operating Segments [Member] | Other [Member]
Segment revenues
Service revenues	9	12	17	30
Product sales	0	14	0	17
Total revenues	$ 9	$ 26	$ 17	$ 47