Business Combination - Summary of Pro Forma Financial Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2018	Jun. 30, 2018
Business Combinations [Abstract]
Pro forma revenue	[1]	$ 2,492	$ 4,845
Pro forma net income attributable to common stockholders	[1]	$ 48	$ 81
Pro forma net income per share attributable to common stockholders
Basic	[1]	$ 0.27	$ 0.45
Diluted	[1]	$ 0.26	$ 0.43
Shares used in the computation of net income per share
Basic	[1],[2]	181	181
Diluted	[1],[2]	188	188

[1] Adjustments, net of tax, included in the pro forma net income above that were of a non-recurring nature totaled $94 million and $109 million for the three and six months ended June 30, 2018. The adjustments reflect the elimination of (1) restructuring and integration costs ($54 million and $62 million), respectively; and (2) transaction costs ($29 million and $36 million) and debt extinguishment costs ($11 million and $11 million) for the three and six months ended June 30, 2018. These pro forma results exclude the effect of adjustments to the opening balance sheet associated with fair value purchase accounting estimates.

[2] Pro forma net income per share was calculated using weighted average basic shares outstanding during the three and six months ended June 30, 2019. Due to the net loss for the three and six months ended June 30, 2019, the effects of stock-based awards, warrants and redeemable preferred stock were not included in the calculation of diluted earnings per share. For the presentation of the pro forma net income for the three and six months ended June 30, 2018, the amount of diluted shares includes the impact of restricted stock and warrants but does not include the impact of the redeemable preferred stock, as those shares were antidilutive