Summary of Significant Accounting Policies - Performance Obligations (Details) $ in Billions	Dec. 31, 2019 USD ($)
Accounting Policies [Abstract]
Revenue from remaining performance obligations	$ 1.1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	48.00%
Performance obligations expected to be satisfied, expected timing	24 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, percentage	39.00%
Performance obligations expected to be satisfied, expected timing	24 months