Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue included in contract liability	$ 223	$ 273	$ 42
Minimum
Disaggregation of Revenue [Line Items]
Contract term	1 year
Maximum
Disaggregation of Revenue [Line Items]
Contract term	5 years
Average | Consumer customers, average contract life
Disaggregation of Revenue [Line Items]
Customer life	30 months
Average | Business customer, average contract life
Disaggregation of Revenue [Line Items]
Customer life	29 months