Restructuring and Asset Impairment Charges (Schedule of Restructuring Charges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Charged to Costs and Expenses	$ 2	$ 17	$ 18
Restructuring charges incurred to date	352
2020-2021 Cost Savings Restructuring Program
Restructuring Reserve [Roll Forward]
Beginning Reserve Balance	5	0
Charged to Costs and Expenses	1	15
Payments and Other	(5)	(10)
Ending Reserve Balance	1	5	0
Restructuring charges incurred to date	17
2020-2021 Cost Savings Restructuring Program | Branch closure charges
Restructuring Reserve [Roll Forward]
Beginning Reserve Balance	3	0
Charged to Costs and Expenses	0	7
Payments and Other	(2)	(4)
Ending Reserve Balance	1	3	0
Restructuring charges incurred to date	8
2020-2021 Cost Savings Restructuring Program | Severance and other
Restructuring Reserve [Roll Forward]
Beginning Reserve Balance	2	0
Charged to Costs and Expenses	1	8
Payments and Other	(3)	(6)
Ending Reserve Balance	0	$ 2	$ 0
Restructuring charges incurred to date	$ 9