Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Jul. 29, 2016	Jul. 31, 2015
Other Comprehensive Income (Loss), Tax
Unrealized gain (loss) on investments, tax expense (benefit)	$ 52	$ (74)
Net change in retirement obligations, tax expense	2	10
Unrealized gain (loss) on derivatives, tax expense (benefit)	$ 30	$ (20)