Deferred Revenue - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contract with Customer, Liability [Abstract]
Total	$ 201	$ 217	$ 216
Deferred revenue, current	129	135	125
Deferred revenue, noncurrent	72	82	$ 91
Deferred revenue recognized	$ 122	$ 114