Segment Information - Additional Information (Details1) $ in Millions	Sep. 30, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Segment Reporting Information [Line Items]
Revenue, remaining performance obligation, amount	$ 344
Revenue, remaining performance obligation, expected timing of satisfaction, period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-04-01
Segment Reporting Information [Line Items]
Revenue, remaining performance obligation, amount	$ 598
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-04-01
Segment Reporting Information [Line Items]
Revenue, remaining performance obligation, amount	$ 1,300
Revenue, remaining performance obligation, expected timing of satisfaction, period