Schedule of Stock Option Activity (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	4 Months Ended	8 Months Ended		12 Months Ended
	Jan. 31, 2014	Sep. 27, 2013		Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Shares of stock under stock options
Outstanding, beginning balance	3.5	4.9		4.9	5.2	6.2
Options granted	0.2	1.4			1.3	1.0
Options forfeited or expired	(0.4)	(1.3)			(1.6)	(0.9)
Options exercised	(0.2)				0	(1.1)
Special dividend adjustments		0.4
Spin-off Adjustment		(1.9)
Outstanding, ending balance	4.5	3.5		4.5	4.9	5.2	6.2
Exercisable at year end	1.9			1.9
Vested and expected to vest in the future as of year end	4.3			4.3
Weighted average exercise price
Outstanding, beginning balance	$ 59.25	$ 67.24		$ 67.24	$ 71.60	$ 69.25
Exercisable at year end	$ 44.36			$ 44.36
Options granted	$ 45.16	$ 54.86			$ 52.79	$ 67.67
Options forfeited or expired	$ 39.43	$ 71.80			$ 70.17	$ 66.91
Options exercised	$ 43.10				$ 0.00	$ 58.75
Outstanding, ending balance	$ 40.33	$ 59.25		$ 40.33	$ 67.24	$ 71.60	$ 69.25
Spin-off Adjustment		$ 57.85
Vested and expected to vest in the future as of year end	$ 40.53			$ 40.53
Weighted average remaining contractual term and Aggregate intrinsic value
Weighted average remaining contractual term, Outstanding	3 years 9 months 18 days	3 years 10 months 24 days			3 years	2 years 6 months	2 years 1 month 6 days
Weighted average remaining contractual term, Vested and expected to vest, years	3 years 7 months 6 days
Aggregate intrinsic value, Outstanding, beginning balance	$ 24					$ 11
Aggregate intrinsic value, Outstanding, Option Exercised	1			8
Aggregate intrinsic value, Outstanding, ending balance	25	24		25			11
Aggregate intrinsic value, Outstanding, Vested and expected to vest	23			23
Stock Split
Shares of stock under stock options
Outstanding, ending balance		4.9	[1]
Weighted average exercise price
Outstanding, ending balance		$ 40.20	[1]
Weighted average remaining contractual term and Aggregate intrinsic value
Weighted average remaining contractual term, Exercisable at year end	1 year 8 months 12 days			1 year 8 months 12 days
Aggregate intrinsic value, Outstanding, ending balance	$ 4			$ 4

[1] Adjusted for Conversion Ratio of 1.4523