Earnings Per Share (EPS) And Dividends (Basic And Diluted Earnings Per Share Computation) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income	$ 471	$ 586
Weighted Average Common Shares Outstanding, Basic (shares)	505	506
Effect of Stock Based Compensation Awards, Basic (shares)	0	0
Total Shares, Basic (shares)	505	506
Net Income, Basic (in dollars per share)	$ 0.93	$ 1.16
Weighted Average Common Shares Outstanding, Diluted (shares)	505	506
Effect of Stock Based Compensation Awards, Diluted (shares)	3	2
Total Shares, Diluted (shares)	508	508
Net Income, Diluted (in dollars per share)	$ 0.93	$ 1.15