Stock Options by Ranges of Exercise Price (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	10,929,371	13,311,652	15,869,417	17,142,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 49.86	$ 50.15	$ 48.53	$ 51.17
Share Based Compensation Options Outstanding Weighted Average Remaining Contractual Term	3 years 3 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 78.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	9,351,182
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 53.89
Share Based Compensation Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term	2 years 5 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	61.00
Range 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	4,548,172
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 19.57
Share Based Compensation Options Outstanding Weighted Average Remaining Contractual Term	6 years 2 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	78.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	2,969,983
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 16.14
Share Based Compensation Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term	5 years 2 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	61.00
Range 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	424,131
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 56.16
Share Based Compensation Options Outstanding Weighted Average Remaining Contractual Term	0 years 1 month
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	0
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	424,131
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 56.16
Share Based Compensation Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term	0 years 1 month
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	0
Range 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,957,068
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 72.54
Share Based Compensation Options Outstanding Weighted Average Remaining Contractual Term	1 year 4 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	0
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	5,957,068
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 72.54
Share Based Compensation Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term	1 year 4 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 0