Restructuring and Related Impairment Charges - 2020 restructuring Plan (Details) - 2020 Restructuring Plan - Forecast $ in Millions	Dec. 31, 2020 USD ($)
Cash Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	$ 175
Facilities and Lease Terminations
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	55
Employee Related Costs
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	25
Contract Termination And Other Restructuring
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	95
Non-Cash Charges
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	350
Long-Lived Asset Impairment
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	290
Intangible and Other Asset Impairment
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	60
Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	475
Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	$ 525