Stock Repurchase Program - Additional Information (Detail) - USD ($)	1 Months Ended			3 Months Ended					4 Months Ended	9 Months Ended
	Jul. 31, 2017	May 31, 2017	Feb. 28, 2017	Jul. 31, 2017	Apr. 30, 2017	Feb. 28, 2017	Jan. 31, 2017	Jul. 31, 2016	May 31, 2017	Jul. 31, 2017	Jul. 31, 2016	Jun. 15, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount	$ 500,000,000			$ 500,000,000						$ 500,000,000		$ 500,000,000
Remaining amount available for further repurchases	500,000,000			$ 500,000,000						$ 500,000,000
Shares repurchased (in shares)				1,627,000				2,525,000		4,401,000	6,889,000
Accelerated Share Repurchase Program December 2016
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount													$ 100,000,000.0
Prepayment amount							$ 100,000,000.0
Accelerated share repurchase, initial share delivery, amount							$ 80,000,000.0
Stock repurchase program, prepayment during prior period, derivative settlement			$ 20,000,000.0
Shares repurchased (in shares)						1,700,000
Average purchase price of shares purchased under agreement (in USD per share)						$ 60.53
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
Prepayment amount					$ 100,000,000.0
Accelerated share repurchase, initial share delivery, amount					$ 80,000,000.0
Stock repurchase program, prepayment during prior period, derivative settlement		$ 20,000,000.0
Shares repurchased (in shares)		265,894							1,400,000
Average purchase price of shares purchased under agreement (in USD per share)									$ 72.02
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
Prepayment amount				$ 100,000,000.0
Accelerated share repurchase, initial share delivery, amount	80,000,000.0			$ 80,000,000.0						$ 80,000,000.0
Stock repurchase program, prepayment during prior period, derivative settlement	$ 20,000,000.0
Shares repurchased (in shares)				1,400,000
Average purchase price of shares purchased under agreement (in USD per share)				$ 73.49