v3.19.3.a.u2
Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Unrealized Loss And Fair Value On Securities [Line Items]    
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value $ 82 $ 486
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 (7)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value 628 974
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (10) (51)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Estimated Fair Value 710 1,460
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss (10) (58)
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value 3,870 4,791
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss (42) (62)
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value 2,610 14,239
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (28) (505)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value 6,480 19,030
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss (70) (567)
US Treasury Securities [Member]    
Unrealized Loss And Fair Value On Securities [Line Items]    
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value   0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss   0
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value   261
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss   (4)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value   261
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss   (4)
Residential Agency [Member]    
Unrealized Loss And Fair Value On Securities [Line Items]    
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value 82 0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value 501 842
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (5) (42)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Estimated Fair Value 583 842
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss (5) (42)
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value 2,402 2,830
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss (11) (37)
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value 2,505 11,010
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (27) (429)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value 4,907 13,840
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss (38) (466)
Commercial Agency [Member]    
Unrealized Loss And Fair Value On Securities [Line Items]    
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value 0 486
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 (7)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value 127 132
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (5) (9)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Estimated Fair Value 127 618
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss (5) (16)
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value 1,449 1,073
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss (31) (13)
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value 73 2,254
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 (51)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value 1,522 3,327
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss (31) (64)
Commercial Non Agency [Member]    
Unrealized Loss And Fair Value On Securities [Line Items]    
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value   229
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss   (1)
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value   404
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss   (9)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value   633
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss   (10)
Corporate and other debt securities [Member]    
Unrealized Loss And Fair Value On Securities [Line Items]    
Available For Sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, Estimated Fair Value 19 659
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 (11)
Available For Sale Securities, Continuous Unrealized Loss Position, Twelve Months or More, Estimated Fair Value 32 310
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss (1) (12)
Available For Sale Securities, Continuous Unrealized Loss, Estimated Fair Value 51 969
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss $ (1) $ (23)