Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Amounts included in contract liability	$ 188	$ 175
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
Weighted Average | Business Customers
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Length of customer life	30 months