Income Taxes (Unrecognized Tax Benefits) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Undistributed Earnings of Foreign Subsidiaries	$ 3,400	$ 5,300
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	94	82	$ 71
Current year tax positions - additions	37	25	14
Prior year tax positions - additions	26	8	5
Pre-acquisition unrecognized tax benefits	0	0	4
Prior year tax positions - reductions	0	(11)	(3)
Statute of limitations expirations	(8)	(8)	(1)
Settlements	(10)	0	(3)
Foreign currency translation	9	(2)	(5)
Ending balance	$ 148	$ 94	$ 82