Additional Information (Schedule of Additional Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development expense	$ 252	$ 241	$ 203
Advertising expense	37	29	27
Interest expense	697	727	754
Interest income	(32)	(31)	(13)
Interest related to NPM Adjustment Items	0	9	6
Interest and other debt expense, net	665	705	747
Rent expense	$ 42	$ 43	$ 53