Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized	$ 29	$ 27	$ 158	$ 146
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			1 year
Length of customer life			12 months
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract term			5 years
Length of customer life			60 months