Revenues - Practical expedients and other revenue disclosures (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Revenue from remaining performance obligation	$ 543
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue from remaining performance obligation	$ 111
Expected period of performance obligation to be recognized	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-01
Revenue from remaining performance obligation	$ 196
Expected period of performance obligation to be recognized	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-07-01
Revenue from remaining performance obligation	$ 87
Expected period of performance obligation to be recognized	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-07-01
Revenue from remaining performance obligation	$ 36
Expected period of performance obligation to be recognized	1 year