Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill by Reporting Segment (Detail) - USD ($) $ in Millions		3 Months Ended			9 Months Ended		12 Months Ended
		Sep. 30, 2019		Mar. 31, 2019	Sep. 30, 2019		Dec. 31, 2018
Goodwill [Line Items]
Balance as of December 31, 2018	[1]			$ 2,654	$ 2,654
Adjustments to finalize purchase accounting estimates	[2]				168
Allocated to APP for disposal					(90)
Currency translation adjustments					(27)
Goodwill impairment		$ (1,370)	[3]	0	(1,370)	[3]	$ (2,200)
Balance as of September 30, 2019		1,335			1,335		2,654	[1]
NCSA [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]			1,041	1,041
Adjustments to finalize purchase accounting estimates	[2]				160
Allocated to APP for disposal					(90)
Goodwill impairment					(1,111)
Balance as of September 30, 2019	[1]						1,041
EARC [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]			421	421
Currency translation adjustments					(12)
Goodwill impairment					(259)
Balance as of September 30, 2019		150			150		421	[1]
MENA [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]			46	46
Adjustments to finalize purchase accounting estimates	[2]				4
Balance as of September 30, 2019		50			50		46	[1]
Technology [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]			$ 1,146	1,146
Adjustments to finalize purchase accounting estimates	[2]				4
Currency translation adjustments					(15)
Balance as of September 30, 2019		$ 1,135			$ 1,135		$ 1,146	[1]

[1] As of December 31, 2018, we had approximately $2.2 billion of cumulative impairment charges recorded in conjunction with our impairment assessment performed during the fourth quarter of 2018, as further described in the 2018 Form 10-K

[2] Our purchase accounting allocation was finalized in the second quarter of 2019. See Note 3, Business Combination for further discussion.

[3] Represents impairment of goodwill associated with our NCSA and EARC reporting units, resulting from our interim impairment assessment during the third quarter of 2019. In addition, in the third quarter of 2019 we recorded $143 million of impairment associated with NCSA intangible assets. The goodwill impairment values are included within the applicable operating segment’s operating loss. See Note 9, Goodwill and Other Intangible Assets, for further discussion.