Deferred Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Deferred revenues	$ 900		$ 900		$ 1,700
Revenue recognized included in beginning deferred revenue	$ 87	$ 54	$ 1,700	$ 1,300