Investment Securities (Cash Flow Model Inputs Used To Calculate Credit Losses) (Details)	Jun. 30, 2020
Minimum [Member]
Debt Securities, Available-for-sale [Line Items]
Prepayment CPR	0.00%
Projected cumulative default	14.00%
Credit support	0.00%
Loss severity	6.00%
Maximum [Member]
Debt Securities, Available-for-sale [Line Items]
Prepayment CPR	25.00%
Projected cumulative default	54.00%
Credit support	19.00%
Loss severity	63.00%