Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized	$ 13	$ 4	$ 197	$ 265
Consumer Customers
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life			30 months
Business Customer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life			29 months
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			1 year
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			5 years