Basic and Diluted Earnings Per Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Numerator:
Net income, as reported	$ 281	$ 258	$ 313	$ 328	$ 309	$ 283	$ 284	$ 223	$ 1,180	$ 1,099	$ 1,116
Less: Net income attributable to participating securities									(3)	(3)	(3)
Net income available to common shareholders									$ 1,177	$ 1,096	$ 1,113
Denominator:
Basic EPS - weighted average shares	366.53	371.01	375.86	378.62	384.87	390.21	390.53	391.45	372.96	389.27	417.32
Effect of dilutive securities:
Stock Options and SARS									0.75	0.86	0.74
Diluted EPS - adjusted weighted average shares and assumed conversions	367.19	371.77	376.61	379.42	385.59	391.05	391.44	392.40	373.71	390.13	418.06
Earnings Per Share:
Basic									$ 3.15	$ 2.82	$ 2.67
Diluted	$ 0.76	$ 0.69	$ 0.83	$ 0.86	$ 0.80	$ 0.72	$ 0.72	$ 0.57	$ 3.15	$ 2.81	$ 2.66