Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		69 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2012	Jan. 31, 2014
Loss Contingencies [Line Items]
Purchase Obligation	$ 1,047		$ 1,047
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Liability	920		920
Net revenues	1,175	$ 1,240	2,331	$ 2,415
GSA Schedule Contract
Loss Contingencies [Line Items]
Net revenues					$ 222
GSA initial analysis of damage exposure						$ 145
GSA Schedule Contract | Minimum
Loss Contingencies [Line Items]
Estimated loss	$ 25		$ 25