SECURITIES - Fair Values and Unrealized Losses of Impaired Securities, by Length of Impairment (Detail) $ in Millions | Mar. 31, 2019USD ($)Security | Dec. 31, 2018USD ($)Security |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 21 | 46 |
Number of available for sale securities, Greater than 1 year | Security | 153 | 136 |
Number of available for sale securities | Security | 174 | 182 |
Securities available for sale, less than 12 months, fair value | $ 196 | $ 679 |
Securities available for sale, 12 months or more, fair value | 2,208 | 1,988 |
Securities available for sale, fair value, total | 2,404 | 2,667 |
Securities available for sale, less than 12 months, unrealized losses | (1) | (7) |
Securities available for sale, 12 months or more, unrealized losses | (37) | (58) |
Securities available for sale, unrealized losses, total | $ (38) | $ (65) |
Number of securities held to maturity positions | Security | 214 | 373 |
Securities held to maturity, less than 12 months, fair value | $ 58 | $ 952 |
Securities held to maturity, greater than 12 months, fair value | 1,944 | 1,720 |
Securities held to maturity, fair value, total | 2,002 | 2,672 |
Securities held to maturity, less than 12 months, unrealized losses | (1) | (31) |
Securities held to maturity, greater than 12 months, unrealized losses | (46) | (73) |
Securities held to maturity, unrealized losses, total | $ (47) | $ (104) |
Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 13 | 210 |
Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 201 | 163 |
US Government Agencies [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 19 | 20 |
Number of available for sale securities, Greater than 1 year | Security | 3 | 0 |
Number of available for sale securities | Security | 22 | 20 |
Securities available for sale, less than 12 months, fair value | $ 123 | $ 145 |
Securities available for sale, 12 months or more, fair value | 48 | 0 |
Securities available for sale, fair value, total | 171 | 145 |
Securities available for sale, less than 12 months, unrealized losses | 0 | (1) |
Securities available for sale, 12 months or more, unrealized losses | (1) | 0 |
Securities available for sale, unrealized losses, total | $ (1) | $ (1) |
U.S. Government-Sponsored Entities [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 0 | 1 |
Number of available for sale securities, Greater than 1 year | Security | 11 | 11 |
Number of available for sale securities | Security | 11 | 12 |
Securities available for sale, less than 12 months, fair value | $ 0 | $ 36 |
Securities available for sale, 12 months or more, fair value | 249 | 227 |
Securities available for sale, fair value, total | 249 | 263 |
Securities available for sale, less than 12 months, unrealized losses | 0 | 0 |
Securities available for sale, 12 months or more, unrealized losses | (2) | (4) |
Securities available for sale, unrealized losses, total | $ (2) | $ (4) |
Number of securities held to maturity positions | Security | 11 | 12 |
Securities held to maturity, less than 12 months, fair value | $ 0 | $ 0 |
Securities held to maturity, greater than 12 months, fair value | 197 | 211 |
Securities held to maturity, fair value, total | 197 | 211 |
Securities held to maturity, less than 12 months, unrealized losses | 0 | 0 |
Securities held to maturity, greater than 12 months, unrealized losses | (3) | (4) |
Securities held to maturity, unrealized losses, total | $ (3) | $ (4) |
U.S. Government-Sponsored Entities [Member] | Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 0 | 0 |
U.S. Government-Sponsored Entities [Member] | Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 11 | 12 |
Agency Mortgage-Backed Securities [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 0 | 16 |
Number of available for sale securities, Greater than 1 year | Security | 85 | 71 |
Number of available for sale securities | Security | 85 | 87 |
Securities available for sale, less than 12 months, fair value | $ 0 | $ 259 |
Securities available for sale, 12 months or more, fair value | 1,288 | 1,159 |
Securities available for sale, fair value, total | 1,288 | 1,418 |
Securities available for sale, less than 12 months, unrealized losses | 0 | (4) |
Securities available for sale, 12 months or more, unrealized losses | (19) | (32) |
Securities available for sale, unrealized losses, total | $ (19) | $ (36) |
Number of securities held to maturity positions | Security | 62 | 90 |
Securities held to maturity, less than 12 months, fair value | $ 0 | $ 294 |
Securities held to maturity, greater than 12 months, fair value | 819 | 694 |
Securities held to maturity, fair value, total | 819 | 988 |
Securities held to maturity, less than 12 months, unrealized losses | 0 | (4) |
Securities held to maturity, greater than 12 months, unrealized losses | (11) | (22) |
Securities held to maturity, unrealized losses, total | $ (11) | $ (26) |
Agency Mortgage-Backed Securities [Member] | Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 0 | 43 |
Agency Mortgage-Backed Securities [Member] | Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 62 | 47 |
Agency Collateralized Mortgage Obligations [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 0 | 2 |
Number of available for sale securities, Greater than 1 year | Security | 48 | 47 |
Number of available for sale securities | Security | 48 | 49 |
Securities available for sale, less than 12 months, fair value | $ 0 | $ 82 |
Securities available for sale, 12 months or more, fair value | 613 | 590 |
Securities available for sale, fair value, total | 613 | 672 |
Securities available for sale, less than 12 months, unrealized losses | 0 | (1) |
Securities available for sale, 12 months or more, unrealized losses | (15) | (22) |
Securities available for sale, unrealized losses, total | $ (15) | $ (23) |
Number of securities held to maturity positions | Security | 48 | 52 |
Securities held to maturity, less than 12 months, fair value | $ 0 | $ 42 |
Securities held to maturity, greater than 12 months, fair value | 591 | 611 |
Securities held to maturity, fair value, total | 591 | 653 |
Securities held to maturity, less than 12 months, unrealized losses | 0 | 0 |
Securities held to maturity, greater than 12 months, unrealized losses | (16) | (24) |
Securities held to maturity, unrealized losses, total | $ (16) | $ (24) |
Agency Collateralized Mortgage Obligations [Member] | Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 0 | 3 |
Agency Collateralized Mortgage Obligations [Member] | Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 48 | 49 |
Non Agency Collateralized Mortgage Obligations [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | | 1 |
Number of available for sale securities, Greater than 1 year | Security | | 0 |
Number of available for sale securities | Security | | 1 |
Securities available for sale, less than 12 months, fair value | | $ 0 |
Securities available for sale, 12 months or more, fair value | | 0 |
Securities available for sale, fair value, total | | 0 |
Securities available for sale, less than 12 months, unrealized losses | | 0 |
Securities available for sale, 12 months or more, unrealized losses | | 0 |
Securities available for sale, unrealized losses, total | | $ 0 |
Commercial Mortgage-Backed Securities [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 2 | 4 |
Number of available for sale securities, Greater than 1 year | Security | 0 | 0 |
Number of available for sale securities | Security | 2 | 4 |
Securities available for sale, less than 12 months, fair value | $ 73 | $ 155 |
Securities available for sale, 12 months or more, fair value | 0 | 0 |
Securities available for sale, fair value, total | 73 | 155 |
Securities available for sale, less than 12 months, unrealized losses | (1) | (1) |
Securities available for sale, 12 months or more, unrealized losses | 0 | 0 |
Securities available for sale, unrealized losses, total | $ (1) | $ (1) |
Number of securities held to maturity positions | Security | 4 | 9 |
Securities held to maturity, less than 12 months, fair value | $ 1 | $ 26 |
Securities held to maturity, greater than 12 months, fair value | 32 | 43 |
Securities held to maturity, fair value, total | 33 | 69 |
Securities held to maturity, less than 12 months, unrealized losses | 0 | 0 |
Securities held to maturity, greater than 12 months, unrealized losses | (1) | (1) |
Securities held to maturity, unrealized losses, total | $ (1) | $ (1) |
Commercial Mortgage-Backed Securities [Member] | Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 1 | 5 |
Commercial Mortgage-Backed Securities [Member] | Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 3 | 4 |
States of the U.S. and Political Subdivisions [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 0 | 2 |
Number of available for sale securities, Greater than 1 year | Security | 5 | 6 |
Number of available for sale securities | Security | 5 | 8 |
Securities available for sale, less than 12 months, fair value | $ 0 | $ 2 |
Securities available for sale, 12 months or more, fair value | 8 | 10 |
Securities available for sale, fair value, total | 8 | 12 |
Securities available for sale, less than 12 months, unrealized losses | 0 | 0 |
Securities available for sale, 12 months or more, unrealized losses | 0 | 0 |
Securities available for sale, unrealized losses, total | $ 0 | $ 0 |
Number of securities held to maturity positions | Security | 89 | 210 |
Securities held to maturity, less than 12 months, fair value | $ 57 | $ 590 |
Securities held to maturity, greater than 12 months, fair value | 305 | 161 |
Securities held to maturity, fair value, total | 362 | 751 |
Securities held to maturity, less than 12 months, unrealized losses | (1) | (27) |
Securities held to maturity, greater than 12 months, unrealized losses | (15) | (22) |
Securities held to maturity, unrealized losses, total | $ (16) | $ (49) |
States of the U.S. and Political Subdivisions [Member] | Less Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 12 | 159 |
States of the U.S. and Political Subdivisions [Member] | Greater Than Twelve Months [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of securities held to maturity positions | Security | 77 | 51 |
Other Debt Securities [Member] | | |
Schedule Of Securities [Line Items] | | |
Number of available for sale securities, Less than 1 year | Security | 0 | 0 |
Number of available for sale securities, Greater than 1 year | Security | 1 | 1 |
Number of available for sale securities | Security | 1 | 1 |
Securities available for sale, less than 12 months, fair value | $ 0 | $ 0 |
Securities available for sale, 12 months or more, fair value | 2 | 2 |
Securities available for sale, fair value, total | 2 | 2 |
Securities available for sale, less than 12 months, unrealized losses | 0 | 0 |
Securities available for sale, 12 months or more, unrealized losses | 0 | 0 |
Securities available for sale, unrealized losses, total | $ 0 | $ 0 |