Stock-Based Compensation - Summary of Options Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Options Outstanding	5,719,468	7,332,137	11,620,393	15,185,729
Weighted-average remaining contractual term (in years)	4 years 1 month 10 days	3 years 8 months 19 days
Options Outstanding, Weighted-Average Exercise Price	$ 41.76	$ 38.14	$ 35.42	$ 34.09
Options Exercisable, Number Exercisable	2,930,368	4,261,817	8,265,818
Options Exercisable, Weighted- Average Exercise Price	$ 34.42	$ 35.37	$ 36.28
15.67 - 30.40 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 15.67
Range of Exercise Prices, Maximum	$ 30.40
Number Of Options Outstanding	461,983
Weighted-average remaining contractual term (in years)	2 years 1 month 10 days
Options Outstanding, Weighted-Average Exercise Price	$ 17.69
Options Exercisable, Number Exercisable	457,386
Options Exercisable, Weighted- Average Exercise Price	$ 17.57
30.87 - 30.87 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 30.87
Range of Exercise Prices, Maximum	$ 30.87
Number Of Options Outstanding	962,124
Weighted-average remaining contractual term (in years)	3 years 11 days
Options Outstanding, Weighted-Average Exercise Price	$ 30.87
Options Exercisable, Number Exercisable	962,124
Options Exercisable, Weighted- Average Exercise Price	$ 30.87
35.93 - 42.92 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 35.93
Range of Exercise Prices, Maximum	$ 42.92
Number Of Options Outstanding	986,616
Weighted-average remaining contractual term (in years)	1 year 1 month 13 days
Options Outstanding, Weighted-Average Exercise Price	$ 40.35
Options Exercisable, Number Exercisable	979,202
Options Exercisable, Weighted- Average Exercise Price	$ 40.37
43.06 - 44.39 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 43.06
Range of Exercise Prices, Maximum	$ 44.39
Number Of Options Outstanding	1,228,295
Weighted-average remaining contractual term (in years)	4 years 8 months 5 days
Options Outstanding, Weighted-Average Exercise Price	$ 44.37
Options Exercisable, Number Exercisable	526,806
Options Exercisable, Weighted- Average Exercise Price	$ 44.35
44.79 - 48.72 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 44.79
Range of Exercise Prices, Maximum	$ 48.72
Number Of Options Outstanding	1,004,375
Weighted-average remaining contractual term (in years)	5 years 8 months 19 days
Options Outstanding, Weighted-Average Exercise Price	$ 45.78
Options Exercisable, Number Exercisable	4,850
Options Exercisable, Weighted- Average Exercise Price	$ 45.49
56.10 - 64.59 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 56.10
Range of Exercise Prices, Maximum	$ 64.59
Number Of Options Outstanding	1,076,075
Weighted-average remaining contractual term (in years)	6 years 6 months 15 days
Options Outstanding, Weighted-Average Exercise Price	$ 56.38
Options Exercisable, Number Exercisable	0
Options Exercisable, Weighted- Average Exercise Price	$ 0.00
15.67 - 64.59 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 15.67
Range of Exercise Prices, Maximum	$ 64.59
Number Of Options Outstanding	5,719,468
Weighted-average remaining contractual term (in years)	4 years 1 month 10 days
Options Outstanding, Weighted-Average Exercise Price	$ 41.76
Options Exercisable, Number Exercisable	2,930,368
Options Exercisable, Weighted- Average Exercise Price	$ 34.42