Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 30, 2015	Oct. 24, 2014	Oct. 30, 2015	Oct. 24, 2014
Other Comprehensive Income (Loss), Tax
Unrealized (loss) gain on investments, tax (benefit) expense	$ (41)	$ (19)	$ (115)	$ 13
Net change in retirement obligations, tax expense	10	6	20	12
Unrealized (loss) gain on derivatives, tax (benefit) expense	$ (13)	$ 68	$ (33)	$ 89