Fair Value (Schedule Of Carrying Values And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Held-to-maturity, fair value	$ 762
Long-term Debt	1,228	$ 724
Fair Value, Inputs, Level 2 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Held-to-maturity	764	774
Time deposits	4,928	4,336
Long-term Debt	1,228	724
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases (including loans held for sale), net of allowance	47,178	46,312
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Held-to-maturity, fair value	762	767
Time deposits	4,921	4,319
Long-term Debt	1,240	727
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases (including loans held for sale), net of allowance	$ 46,197	$ 45,251