Restructuring Costs - Narrative (Details) $ in Millions	Sep. 30, 2018 USD ($)
Fiscal 2018 Plan
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	$ 813
Fiscal 2018 Plan | Workforce Reductions
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	616
Fiscal 2018 Plan | Facilities Costs
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	197
Fiscal 2017 Plan
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	215
Fiscal 2017 Plan | Workforce Reductions
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	207
Fiscal 2017 Plan | Facilities Costs
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	$ 8