Acquisitions, Divestitures and Restructuring Activities - Narrative Restructuring (Details) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2020 employee	Jun. 30, 2020 employee	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Staffing reduction, employees | employee	300	50
Restructuring charges			$ 0	$ 74	$ 1	$ 75
Employee severance | 2020 Corporate Restructuring
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring charges				$ 74		74
Accelerated vesting of certain equity awards | 2020 Corporate Restructuring
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring charges						$ 3