Fair Value Measurements , Valuation Techniques (Details) - Recurring - Level 3 - USD ($) $ in Millions	12 Months Ended
	Apr. 24, 2015	Apr. 25, 2014
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	$ 106	$ 127
Total realized losses and other-than-temporary impairment losses included in earnings	(5)	(5)
Total unrealized gains included in other comprehensive income	10	4
Settlements	(5)	(20)
Ending balance	106	106
Corporate Debt Securities
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	9	10
Total realized losses and other-than-temporary impairment losses included in earnings	(5)	0
Total unrealized gains included in other comprehensive income	2	0
Settlements	(5)	(1)
Ending balance	$ 1	9
Auction Rate Securities
Fair Value Inputs
Illiquidity premium	6.00%
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	$ 97	103
Total realized losses and other-than-temporary impairment losses included in earnings	0	(5)
Total unrealized gains included in other comprehensive income	8	3
Settlements	0	(4)
Ending balance	$ 105	97
Auction Rate Securities | Minimum
Fair Value Inputs
Years to Principal Recovery	2 years
Auction Rate Securities | Maximum
Fair Value Inputs
Years to Principal Recovery	12 years
Auction Rate Securities | Weighted Average
Fair Value Inputs
Years to Principal Recovery	3 years
Mortgage Backed Securities
Reconciliation of Retirement Benefit Plan Assets Measured at Fair Value Using Significant Unobservable Inputs
Beginning balance	$ 0	14
Total realized losses and other-than-temporary impairment losses included in earnings	0	0
Total unrealized gains included in other comprehensive income	0	1
Settlements	0	(15)
Ending balance	$ 0	$ 0