Basis Of Presentation And Recently Issued Accounting Pronouncements (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basis Of Presentation And Recently Issued Accounting Pronouncements [Abstract]
Net unrealized gain or loss on foreign-currency transactions of intercompany loan hedges	$ 0	$ (3)
Employee Service Share Based Compensation Incremental Tax Benefit To Be Realized From Exercise Of Stock Awards	$ 56
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense		$ 9