Fair Value (Schedule of Carrying Values and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
HTM investment securities	$ 622	$ 640
Time deposits	1,940	2,588
Long-term debt	1,308	1,336
Level 2 | Carrying value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
HTM investment securities	620	636
Time deposits	1,940	2,588
Long-term debt	1,308	1,336
Level 2 | Estimated fair value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
HTM investment securities	622	640
Time deposits	1,949	2,603
Long-term debt	1,338	1,346
Level 3 | Carrying value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases (including loans held for sale), net of allowance	50,929	52,780
Level 3 | Estimated fair value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases (including loans held for sale), net of allowance	$ 51,436	$ 53,221