Schedule of Information Related to Stock Repurchase Programs (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2019	Dec. 31, 2016	Dec. 31, 2014
Class of Stock [Line Items]
Additional dollars authorized for repurchase		$ 2,700,000,000			$ 1,000,000,000.0		$ 1,700,000,000
Aggregate purchase price paid for shares purchased as part of publicly announced program		$ 753,927,000	$ 414,002,000	$ 356,413,000
Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs		11,680,564
Average price paid per share for shares purchased as part of publicly announced program		$ 122.41
Aggregate purchase price paid for shares purchased as part of publicly announced program		$ 1,429,768,000
Stock Repurchase Programs Twenty Sixteen
Class of Stock [Line Items]
Maximum number of dollars that may yet be purchased under the program						$ 285,891,000
Stock Repurchase Programs Twenty Seventeen
Class of Stock [Line Items]
Additional dollars authorized for repurchase				$ 400,000,000
Total number of shares purchased	[1]			3,266,121
Total number of shares cancelled				10,791
Average price paid per share for forfeited restricted shares				$ 0.01
Total number of shares purchased as part of publicly announced programs				2,960,843
Aggregate purchase price paid				$ 356,413,000
Aggregate purchase price paid for shares purchased as part of publicly announced program				322,200,000
Maximum number of dollars that may yet be purchased under the program				$ 363,660,000
Stock Repurchase Programs Twenty Seventeen | Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs				2,960,843
Average price paid per share for shares purchased as part of publicly announced program				$ 108.83
Aggregate purchase price paid for shares purchased as part of publicly announced program				$ 322,231,000
Stock Repurchase Programs Twenty Eighteen
Class of Stock [Line Items]
Additional dollars authorized for repurchase			$ 500,000,000
Total number of shares purchased	[1]		3,435,992
Total number of shares cancelled			11,224
Average price paid per share for forfeited restricted shares			$ 0.01
Total number of shares purchased as part of publicly announced programs			3,321,968
Aggregate purchase price paid			$ 414,002,000
Aggregate purchase price paid for shares purchased as part of publicly announced program			401,300,000
Maximum number of dollars that may yet be purchased under the program			$ 462,344,000
Stock Repurchase Programs Twenty Eighteen | Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs			3,321,968
Average price paid per share for shares purchased as part of publicly announced program			$ 120.81
Aggregate purchase price paid for shares purchased as part of publicly announced program			$ 401,316,000
Stock Repurchase Programs Twenty Nineteen
Class of Stock [Line Items]
Additional dollars authorized for repurchase		$ 1,000,000,000
Total number of shares purchased	[1]	5,762,409
Total number of shares cancelled		27,713
Average price paid per share for forfeited restricted shares		$ 0.01
Total number of shares purchased as part of publicly announced programs		5,397,753
Aggregate purchase price paid		$ 753,928,000
Aggregate purchase price paid for shares purchased as part of publicly announced program		706,200,000
Maximum number of dollars that may yet be purchased under the program		$ 756,123,000
Stock Repurchase Programs Twenty Nineteen | Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs		5,397,753
Average price paid per share for shares purchased as part of publicly announced program		$ 130.84
Aggregate purchase price paid for shares purchased as part of publicly announced program		$ 706,221,000
Stock Repurchase Programs Twenty Seventeen to Twenty Nineteen
Class of Stock [Line Items]
Additional dollars authorized for repurchase		$ 1,900,000,000
Total number of shares purchased	[1]	12,464,522
Total number of shares cancelled		49,728
Average price paid per share for forfeited restricted shares		$ 0.01
Aggregate purchase price paid		$ 1,524,343,000

[1] Includes 27,713, 11,224 and 10,791 of restricted shares that were forfeited by former employees pursuant to the terms of our restricted stock purchase plan during 2019, 2018 and 2017, respectively.