Restructuring and Transaction Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs	$ 0	$ 189
Reduction Of Workforce [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs		21
Noncash restructuring costs		37
Transaction Costs [Member]
Restructuring Cost And Reserve [Line Items]
Transaction costs		46
Merger Integration [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring and transaction costs		$ 143