Statements of Cash Flows - Supplemental Cash Flows and Non Cash Investing and Financing Activities (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	9 Months Ended
	Nov. 14, 2012	Jan. 24, 2014	Jan. 25, 2013
Non-cash Investing and Financing Activities:
Reclassification of equity component of Convertible Notes		$ 0	$ 62.6
Acquisition of property and equipment outstanding in accounts payable		25.7	30.4
Acquisition of software through long-term financing		11.4	0.8
Vested options assumed in acquisition	1.2	0	1.2
Supplemental Cash Flow Information:
Income taxes paid, net of refunds		39.5	33.9
Interest paid, net of capitalized interest		$ 35.0	$ 22.6