Stock Repurchase Program - Additional Information (Detail) - USD ($)		1 Months Ended						3 Months Ended			4 Months Ended	12 Months Ended
	Dec. 13, 2017	Nov. 30, 2017	Sep. 30, 2017	Jul. 31, 2017	May 31, 2017	Feb. 28, 2017	Dec. 31, 2016	Nov. 30, 2017	Jul. 31, 2017	Feb. 28, 2017	May 31, 2017	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015	Jun. 15, 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount												$ 500,000,000.0			$ 500,000,000
Remaining amount available for further repurchases												$ 400,000,000
Average purchase price (in USD per share)												$ 70.21	$ 49.37	$ 45.84
Purchases of treasury stock (in shares)												5,413,000	8,506,000	5,672,000
Accelerated Share Repurchase Program December 2016
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount							$ 100,000,000
Average purchase price (in USD per share)										$ 60.53
Stock repurchase program, prepayment during period							100,000,000
Accelerated share repurchase, initial share delivery, amount							$ 80,000,000
Stock repurchase program, prepayment during period, derivative settlement						$ 20,000,000
Purchases of treasury stock (in shares)										1,700,000
Accelerated Share Repurchase Program February 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount						100,000,000.0				$ 100,000,000.0
Average purchase price (in USD per share)											$ 72.02
Stock repurchase program, prepayment during period						100,000,000
Accelerated share repurchase, initial share delivery, amount						$ 80,000,000				$ 80,000,000
Stock repurchase program, prepayment during period, derivative settlement					$ 20,000,000
Purchases of treasury stock (in shares)											1,400,000
Accelerated Share Repurchase Program May 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount					100,000,000.0						$ 100,000,000.0
Average purchase price (in USD per share)									$ 73.49
Stock repurchase program, prepayment during period					100,000,000
Accelerated share repurchase, initial share delivery, amount					$ 80,000,000						$ 80,000,000
Stock repurchase program, prepayment during period, derivative settlement				$ 20,000,000
Purchases of treasury stock (in shares)									1,400,000
Accelerated Share Repurchase Program September 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount			$ 100,000,000.0
Stock repurchase program, prepayment during period			100,000,000
Accelerated share repurchase, initial share delivery, amount			$ 80,000,000
Subsequent Event | Accelerated Share Repurchase Program September 2017
Equity, Class of Treasury Stock [Line Items]
Share repurchases settlement of equity forward (in shares)		181,988
Average purchase price (in USD per share)								$ 83.80
Stock repurchase program, prepayment during period, derivative settlement		$ 20,000,000
Purchases of treasury stock (in shares)								1,200,000
Subsequent Event | Accelerated Share Repurchase Program December 2017
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount	$ 200,000,000.0
Stock repurchase program, prepayment during period	200,000,000
Accelerated share repurchase, initial share delivery, amount	160,000,000
Stock repurchase program, prepayment during period, derivative settlement	$ 40,000,000