Investing Activities (Tables)

12 Months Ended

Dec. 31, 2017

Impairment of equity-method investments

The following table presents other-than-temporary impairment charges related to certain equity-method investments (see Note 16 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk):



	Years Ended December 31,
	2016		2015
	(Millions)
Williams Partners
Appalachia Midstream Investments	$	294	$	562
DBJV	59		503
Laurel Mountain	50		45
UEOM	—		241
Ranch Westex	24		—
Other	3		8
	$	430	$	1,359

Investments [Table Text Block]

Investments



	Ownership Interest at December 31, 2017	December 31,
	Ownership Interest at December 31, 2017	2017		2016
		(Millions)
Equity-method investments:
Appalachia Midstream Investments	(1)	$	3,104	$	2,062
UEOM	62%	1,383		1,448
Discovery	60%	534		572
Caiman II	58%	429		426
OPPL	50%	422		430
Laurel Mountain	69%	309		324
Gulfstream	50%	244		261
DBJV	—	—		988
Other	Various	127		190
		$	6,552	$	6,701

___________


(1)	Includes equity-method investments in multiple gathering systems in the Marcellus Shale with an approximate average 66 percent interest.

Contributions [Table Text Block]

Purchases of and contributions to equity-method investments

We generally fund our portion of significant expansion or development projects of these investees through additional capital contributions. These transactions increased the carrying value of our investments and included:



	Years Ended December 31,
	2017		2016		2015
	(Millions)
Appalachia Midstream Investments	$	70	$	28	$	93
DBJV	32		105		57
Caiman II	24		22		—
Discovery	1		—		35
UEOM	—		—		357
Other	5		22		53
	$	132	$	177	$	595

Dividends and distributions [Table Text Block]

Dividends and distributions

The organizational documents of entities in which we have an equity-method interest generally require distribution of available cash to members on at least a quarterly basis. These transactions reduced the carrying value of our investments and included:



	Years Ended December 31,
	2017		2016		2015
	(Millions)
Appalachia Midstream Investments	$	270	$	211	$	219
Discovery	127		141		116
Gulfstream	92		100		88
UEOM	80		92		42
OPPL	68		69		45
Caiman II	49		40		33
DBJV	39		39		33
Laurel Mountain	32		28		31
Other	27		22		26
	$	784	$	742	$	633

Summarized Financial Position and Results of Operations of Equity Method Investments [Table Text Block]

Summarized Financial Position and Results of Operations of All Equity-Method Investments



	December 31,
	2017			2016
	(Millions)
Assets (liabilities):
Current assets	$	447		$	508
Noncurrent assets	9,181			9,695
Current liabilities	(295		)	(412		)
Noncurrent liabilities	(1,538		)	(1,484		)



	Years Ended December 31,
	2017		2016		2015
	(Millions)
Gross revenue	$	1,961	$	1,883	$	1,707
Operating income	871		799		690
Net income	806		726		611