Stock-based Compensation Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value of stock options outstanding	$ 840
Aggregate intrinsic value of stock options exercisable	463
Total intrinsic value of options exercised	176	142	246
Total unrecognized compensation cost related to nonvested stock-based compensation arrangements	502
Expected to be recognized in 2014	232
Expected to be recognized in 2015	161
Expected to be recognized in 2016	75
Expected to be recognized in 2017	28
Expected to be recognized in 2018	$ 6
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average remaining contractual life of stock options exercisable, in years	5 years 1 month 6 days
Stock option maximum term	10 years
Stock options vesting period	Four or Five Years
Restricted stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock awards, vesting period	3 years
DSPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage purchase price of stock lower of stock price at beginning or end of plan period at specified intervals	92.50%