Revenue from Contracts With Customers - Performance obligations (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Practical Expedient, Initial Application and Transition, Nondisclosure of Transaction Price Allocation to Remaining Performance Obligation [true false]	true
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 2,280
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period in which remaining performance obligations expect to be satisfied and revenue recognized	12 months
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 1,371
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period in which remaining performance obligations expect to be satisfied and revenue recognized
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 909