Goodwill and Other Intangible Assets - Summary of Core Deposit Intangibles, Customer Renewal Lists and Mortgage Servicing Rights (Detail) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
---|---|---|
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | $ 211 | $ 208 |
Accumulated amortization | (132) | (116) |
Net carrying amount | 79 | 92 |
Core Deposit Intangibles | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | 196 | 196 |
Accumulated amortization | (122) | (107) |
Net carrying amount | 74 | 89 |
Customer Renewal Lists | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | 15 | 12 |
Accumulated amortization | (10) | (9) |
Net carrying amount | $ 5 | $ 3 |