Quarterly report pursuant to Section 13 or 15(d)

HELD-TO-MATURITY SECURITIES - Amortized Cost, Gross Unrealized Gains and Losses, & Fair Value (Details)

v3.10.0.1
HELD-TO-MATURITY SECURITIES - Amortized Cost, Gross Unrealized Gains and Losses, & Fair Value (Details) - USD ($)
$ in Millions
Sep. 30, 2018
Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost $ 8,465 $ 9,091
Unrealized Gross Gains 0 4
Unrealized Gross Losses (353) (124)
Fair Value 8,112 8,971
Collateralized Mortgage Obligations [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 2,203 3,714
Unrealized Gross Gains 0 1
Unrealized Gross Losses (95) (58)
Fair Value 2,108 3,657
Residential Mortgage Backed Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 1,624 1,049
Unrealized Gross Gains 0 2
Unrealized Gross Losses (69) (7)
Fair Value 1,555 1,044
Commercial Mortgage Backed Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 4,271 3,791
Unrealized Gross Gains 0 0
Unrealized Gross Losses (177) (55)
Fair Value 4,094 3,736
Federal agencies, Other agencies    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 362 532
Unrealized Gross Gains 0 1
Unrealized Gross Losses (12) (4)
Fair Value 350 529
Total U.S. Treasury, Federal agency and other agency securities    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 8,460 9,086
Unrealized Gross Gains 0 4
Unrealized Gross Losses (353) (124)
Fair Value 8,107 8,966
Municipal securities    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 5 5
Unrealized Gross Gains 0 0
Unrealized Gross Losses 0 0
Fair Value $ 5 $ 5