Revenue from Contracts with Customers - Transaction Price Allocated to Unsatisfied Obligations (Details) $ in Millions	Dec. 31, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Remaining unsatisfied obligations	$ 2,732
Amount of of customer only general cancellation	1,923
Amount of non-cancelable contracts	312
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Remaining unsatisfied obligations	$ 1,377
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Remaining unsatisfied obligations	$ 1,355
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period