Fair Value Measurements (Schedule Of Available For Sale Securities) (Details) - USD ($) $ in Millions	Dec. 29, 2018	Sep. 29, 2018
U.S. treasury and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost Basis	$ 47	$ 48
Fair Value	47	47
Unrealized Gain (Loss)	0	(1)
Corporate and asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost Basis	53	52
Fair Value	52	51
Unrealized Gain (Loss)	$ (1)	$ (1)