Segment and Geographic Information (Reconciliation Of Total Segment Income From Operations To Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting [Abstract]
Income from operations for reportable segments	$ 207	$ 396	$ 404	$ 401	$ 363	$ 364	$ 264	$ 234	$ 1,408	$ 1,225	$ 583
Interest expense									(126)	(159)	(79)
Other income, net									52	15	54
Income before income taxes									$ 1,334	$ 1,081	$ 558