Leasing (Lease, Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 11	$ 11	$ 35	$ 34
Variable lease expense	2	2	6	6
Total lease expense, net	$ 13	$ 13	$ 41	$ 40