Fair Value (Nonrecurring Fair Value Measurements) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets - gains (losses)	$ (49)	$ (140)	$ (84)
Nonaccrual loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets - gains (losses)	(4)	(111)	(76)
OREO and Foreclosed Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets - gains (losses)		(2)	(5)
Long-lived Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	103	20
Total assets - gains (losses)	(45)	(27)	$ (3)
Fair Value of Property or Collateral
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	457	370
Fair Value of Property or Collateral | Nonaccrual loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	348	332
Fair Value of Property or Collateral | OREO and Foreclosed Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 6	$ 18