Restructuring Costs - Narrative (Details) $ in Millions	Dec. 31, 2018 USD ($)
Fiscal 2018 Plan
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	$ 806
Fiscal 2018 Plan | Workforce Reductions
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	614
Fiscal 2018 Plan | Facilities Costs
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	192
Fiscal 2017 Plan
Restructuring Cost and Reserve [Line Items]
Total Costs Incurred to Date	216
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	$ 9