Segment Information - Reconciliation of Segments' Earnings from Operations to Company's Consolidated Earnings from Operations Before Income Taxes (Detail) (USD $)	3 Months Ended	12 Months Ended
	Oct. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Segment Reporting [Abstract]
Repayment of Long-term Debt		$ 400,000,000	$ 0	$ 60,000,000
Earnings from operations for segments		1,028,494,000	934,570,000	823,638,000
Unallocated corporate expenses		(137,065,000)	(140,651,000)	(126,421,000)
Interest expense, financing costs and other income, net		(60,113,000)	(49,463,000)	(53,641,000)
Loss on Extinguishment of Debt	(93,779,000)	(93,779,000)	0	0
Other operating expense		0	(489,590,000)	0
Earnings from operations before income taxes		$ 737,537,000	$ 254,866,000	$ 643,576,000