Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended			6 Months Ended		12 Months Ended
	Nov. 01, 2017	Sep. 29, 2017	Jun. 30, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016	Mar. 31, 2017
Class of Stock [Line Items]
Dividends declared per common share (in usd per share)		$ 0.075		$ 0.075	$ 0.15	$ 0.15
Stock Repurchase Program
Class of Stock [Line Items]
Remaining authorized repurchase amount		$ 800			$ 800
Common Stock | Accelerated Stock Repurchase Agreement
Class of Stock [Line Items]
Accelerated stock repurchase program, authorized amount							$ 500
Accelerated stock repurchase program, upfront payment							$ 500
Accelerated stock repurchase program, shares repurchased in the period (in shares)			2.2		16.4		14.2
Accelerated stock repurchase program, average price paid per share					$ 30.51
Subsequent Event | Common Stock
Class of Stock [Line Items]
Dividends declared per common share (in usd per share)	$ 0.075