Restructuring - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Total expected pre-tax restructuring charges	$ 310
2019 Restructuring
Restructuring Cost and Reserve [Line Items]
Total expected pre-tax restructuring charges	$ 310
Percentage expected to be paid with cash on hand	70.00%
2019 Restructuring | Severance and employee-related costs
Restructuring Cost and Reserve [Line Items]
Percentage of aggregate charge	60.00%
2019 Restructuring | Facilities and related costs
Restructuring Cost and Reserve [Line Items]
Percentage of aggregate charge	20.00%
2019 Restructuring | Other costs
Restructuring Cost and Reserve [Line Items]
Percentage of aggregate charge	20.00%