Revenues - Practical expedients and other revenue disclosures (Detail) $ in Millions	Mar. 31, 2020 USD ($)
Revenue from remaining performance obligation	$ 514
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue from remaining performance obligation	$ 55
Expected period of performance obligation to be recognized	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue from remaining performance obligation	$ 206
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	$ 102
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	$ 37
Expected period of performance obligation to be recognized	1 year