Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized	$ 495	$ 490
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