Income Taxes (Unrecognized Tax Benefits) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Undistributed Earnings of Foreign Subsidiaries	$ 4,100	$ 3,600
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	167	166	$ 148
Current year tax positions - additions	25	25	36
Prior year tax positions - additions	5	4	17
Prior year tax positions - reductions	(2)	(9)	(6)
Statute of limitations expirations	(8)	(6)	(9)
Settlements	(11)	(12)	(15)
Foreign currency translation	(1)	(1)	(5)
Ending balance	$ 175	$ 167	$ 166