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	$ 59	$ 44	$ 554	$ 534
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			1 year
Minimum | Business Customer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life			12 months
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			5 years
Maximum | Business Customer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life			60 months
Weighted Average | Consumer Customers
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life			30 months