Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill by Reporting Segment (Detail) - USD ($) $ in Millions		3 Months Ended						12 Months Ended
		Dec. 31, 2019		Sep. 30, 2019	[3]	Dec. 31, 2018		Dec. 31, 2019		Dec. 31, 2018
Goodwill [Line Items]
Balance as of December 31, 2018	[1]							$ 2,654
Adjustments to finalize purchase accounting estimates	[2]							168
Allocation to APP disposition								(90)
Currency translation adjustments								(16)
Goodwill impairment		$ (60)	[3]	$ (1,370)		$ (2,168)	[4],[5]	(1,430)	[6]	$ (2,168)	[6]
Balance as of December 31, 2019		1,286				2,654	[1]	1,286		2,654	[1]
NCSA [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]							1,041
Adjustments to finalize purchase accounting estimates	[2]							160
Allocation to APP disposition								(90)
Goodwill impairment								(1,111)
Balance as of December 31, 2019	[1]					1,041				1,041
EARC [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]							421
Currency translation adjustments								(5)
Goodwill impairment		(59)						(319)
Balance as of December 31, 2019		97				421	[1]	97		421	[1]
MENA [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]							46
Adjustments to finalize purchase accounting estimates	[2]							4
Balance as of December 31, 2019		50				46	[1]	50		46	[1]
Technology [Member]
Goodwill [Line Items]
Balance as of December 31, 2018	[1]							1,146
Adjustments to finalize purchase accounting estimates	[2]							4
Currency translation adjustments								(11)
Balance as of December 31, 2019		$ 1,139				$ 1,146	[1]	$ 1,139		$ 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 previously 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] 2019—represents impairment of goodwill associated with our NCSA and EARC reporting units, resulting from our interim and annual impairment assessment. See Note 9, Goodwill and Other Intangible Assets, for further discussion.

[4] 2018—represents impairment of goodwill associated with our NCSA, EARC, APAC and Technology reporting units, resulting from our annual impairment assessment.

[5] Results in the second, third and fourth quarters of 2018 reflect impacts of the Combination from the Combination Date.

[6] Represents impairment of goodwill associated with our NCSA and EARC reporting units in 2019 and our NCSA, EARC, APAC and Technology reporting units in 2018. See Note 9, Goodwill and Other Intangible Assets, for further discussion. The goodwill impairment values are included within the applicable operating group’s Operating loss.