Goodwill (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The following is the summary of change in the carrying amount of goodwill for the years ended December 31:

	2018		2017
	(In millions)
Balance as of January 1	$	2,293	$	2,286
Goodwill attributable to Gas Storage and Pipelines 2016 acquisition of AGS and SGG	—		7
Balance at December 31	$	2,293	$	2,293