Segment Disclosures Reconciliation of Segment Revenues to Consolidated (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment revenues
Service revenues	$ 1,310	$ 1,247	$ 3,853	$ 3,678
Product sales	581	658	1,950	1,623
Total revenues	1,891	1,905	5,803	5,301
Williams Partners [Member]
Segment revenues
Service revenues	1,304	1,241	3,836	3,656
Product sales	581	655	1,950	1,613
Other [Member]
Segment revenues
Service revenues	6	6	17	22
Product sales	0	3	0	10
Intersegment Elimination [Member]
Segment revenues
Service revenues	(2)	(14)	(9)	(49)
Product sales	0	(6)	0	(16)
Total revenues	(2)	(20)	(9)	(65)
Intersegment Elimination [Member] | Williams Partners [Member]
Segment revenues
Service revenues	0	(11)	(1)	(32)
Product sales	0	0	0	0
Intersegment Elimination [Member] | Other [Member]
Segment revenues
Service revenues	(2)	(3)	(8)	(17)
Product sales	0	(6)	0	(16)
Operating Segments [Member] | Williams Partners [Member]
Segment revenues
Service revenues	1,304	1,252	3,837	3,688
Product sales	581	655	1,950	1,613
Total revenues	1,885	1,907	5,787	5,301
Operating Segments [Member] | Other [Member]
Segment revenues
Service revenues	8	9	25	39
Product sales	0	9	0	26
Total revenues	$ 8	$ 18	$ 25	$ 65