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Loans - Additional Information (Detail) - USD ($) $ in Millions | Mar. 31, 2020 | Dec. 31, 2019
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Loans and Leases Receivable Disclosure [Line Items] |  |
Accrued interest receivable | $ 1,400 |
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend | 337 | $ 178
Loans held for sale | 1,056 | 400
Performing |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Troubled debt restructurings included in impaired loans | 1,700 | 1,700
Federal Home Loan banks |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Loans Pledged as Collateral | 15,500 | 14,600
Line of Credit Facility, Remaining Borrowing Capacity | 18,900 | 18,700
Federal Reserve Discount Window |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Loans Pledged as Collateral | 6,200 | 6,700
Line of Credit Facility, Remaining Borrowing Capacity | 4,900 | 5,300
Consumer Banking | Performing |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Troubled debt restructurings included in impaired loans | 1,200 | 1,100
Commercial Banking | Performing |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Troubled debt restructurings included in impaired loans | 249 | $ 224
Domestic credit card: | Credit Card |  |
Loans and Leases Receivable Disclosure [Line Items] |  |
Financing Receivable, Past Due, Revolving, Converted To Term Loan | $ 160 |

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- Definition Amount of financing receivable modified as troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554 + Details
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- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554 + Details
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- Definition Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5086-111524 + Details
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