Leases (Components Of Lease Cost) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Amortization of right-of-use assets	$ 4	$ 6
Interest on lease liabilities	4	8
Finance lease cost	8	14
Operating lease cost	17	37
Sublease income	(3)	(7)
Total Lease cost	22	44
Short-term lease cost	1	2
Variable lease cost	$ 1	$ 4