Restructuring and Related Implementation Charges - Summary of Restructuring Charges, Cumulative to Date (Details) - Global Growth and Efficiency Program $ in Millions	Mar. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Pretax charges related to the Restructuring Program to date	$ 1,751
Aftertax charges related to the Restructuring Program to date	1,300
Employee-Related Costs
Restructuring Cost and Reserve [Line Items]
Pretax charges related to the Restructuring Program to date	691
Incremental Depreciation
Restructuring Cost and Reserve [Line Items]
Pretax charges related to the Restructuring Program to date	97
Asset Impairments
Restructuring Cost and Reserve [Line Items]
Pretax charges related to the Restructuring Program to date	58
Other
Restructuring Cost and Reserve [Line Items]
Pretax charges related to the Restructuring Program to date	$ 905