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		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net Income	$ 403	$ 412	$ 1,256	$ 1,239
Weighted Average Common Shares Outstanding, Basic (shares)	504	504	504	504
Effect of Stock Based Compensation Awards, Basic (shares)	0	0	0	0
Total Shares, Basic (shares)	504	504	504	504
Net Income, Basic (dollars per share)	$ 0.80	$ 0.82	$ 2.49	$ 2.46
Weighted Average Common Shares Outstanding, Diluted (shares)	504	504	504	504
Effect of Stock Based Compensation Awards, Diluted (shares)	3	3	3	3
Total Shares, Diluted (shares)	507	507	507	507
Net Income, Diluted (dollars per share)	$ 0.79	$ 0.81	$ 2.47	$ 2.44