Premises and Equipment (Schedule of Premises and Equipment) (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | $ 4,614 | $ 4,603 |
| Accumulated depreciation and amortization | (2,654) | (2,558) |
| Premises and equipment, net | 1,960 | 2,045 |
| Land | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | 446 | 481 |
| Premises and improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | 1,783 | 1,830 |
| Furniture and equipment | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | 1,023 | 994 |
| Software | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | 756 | 699 |
| Leasehold improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | 407 | 379 |
| Construction in progress | ||
| Property, Plant and Equipment [Line Items] | ||
| Premises and equipment, gross | $ 199 | $ 220 |