Consolidated Statement of Changes in Equity (Unaudited) - 9 months ended Sep. 30, 2018 - USD ($) $ in Millions	Total	Total Stockholders’ Equity	Preferred Stock [Member]	Common Stock	Capital in Excess of Par Value	Retained Deficit	AOCI	Treasury Stock	Noncontrolling Interests
December 31, 2017 at Dec. 31, 2017	$ 16,175	$ 9,656	$ 0	$ 861	$ 18,508	$ (8,434)	$ (238)	$ (1,041)	$ 6,519
Adoption of ASC 606 (Note 1)	(121)	(84)	0	0	0	(84)	0	0	(37)
Adoption of ASU 2018-02 (Note 1)	0	0	0	0	0	61	(61)	0	0
Net income (loss)	739	416	0	0	0	416	0	0	323
Other comprehensive income (loss)	9	11	0	0	0	0	11	0	(2)
WPZ Merger (Note 1)	1,862	6,491	0	382	6,112	0	(3)	0	(4,629)
Issuance of preferred stock (Note 11)	35	35	35	0	0	0	0	0	0
Cash dividends – common stock	(974)	(974)	0	0	0	(974)	0	0	0
Dividends and distributions to noncontrolling interests	(598)	0	0	0	0	0	0	0	(598)
Stock-based compensation and related common stock issuances	49	49	0	1	48	0	0	0	0
Sales of limited partner units of Williams Partners L.P.	46	0	0	0	0	0	0	0	46
Changes in ownership of consolidated subsidiaries, net	(4)	14	0	0	14	0	0	0	(18)
Contributions from noncontrolling interests	13	0	0	0	0	0	0	0	13
Deconsolidation of subsidiary (Note 3)	(267)	0	0	0	0	0	0	0	(267)
Other	(5)	(4)	0	1	(2)	(3)	0	0	(1)
Net increase (decrease) in equity	784	5,954	35	384	6,172	(584)	(53)	0	(5,170)
September 30, 2018 at Sep. 30, 2018	$ 16,959	$ 15,610	$ 35	$ 1,245	$ 24,680	$ (9,018)	$ (291)	$ (1,041)	$ 1,349