Leasing (Lease, Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating lease expense	$ 14	$ 11	$ 26	$ 24
Variable lease expense	2	2	4	4
Total lease expense, net	$ 16	$ 13	$ 30	$ 28