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Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Allowance for Loan and Lease Losses and Reserve for Unfunded Lending Commitments Activity (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | $ 7,208 |  |
Provision for credit losses |  | 10,264 | $ 6,236 | $ 5,856
Balance at the end of the period |  | 15,564 | 7,208 |
Other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Provision for credit losses |  | 3 | 0 | (49)
Allowance for credit losses |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 7,208 | 7,220 | 7,502
Charge-offs |  | (7,677) | (8,809) | (8,615)
Recoveries |  | 2,452 | 2,557 | 2,503
Net charge-offs |  | (5,225) | (6,252) | (6,112)
Provision for credit losses |  | 10,238 | 6,223 | 5,858
Allowance build (release) for credit losses |  | 5,013 | (29) | (254)
Other changes |  | 36 | 17 | (28)
Balance at the end of the period |  | 15,564 | 7,208 | 7,220
Allowance for credit losses | Other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  |  | 0 | 1
Charge-offs |  |  |  | (7)
Recoveries |  |  |  | 1
Net charge-offs |  |  |  | (6)
Provision for credit losses |  |  |  | (49)
Allowance build (release) for credit losses |  |  |  | (55)
Other changes |  |  |  | 54
Balance at the end of the period |  |  |  | 0
Allowance for credit losses | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 2,845 |  |
Balance at the end of the period |  |  | 2,845 |
Allowance for credit losses | Finance charge and fee reserve reclassification |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 462 |  |
Balance at the end of the period |  |  | 462 |
Allowance for credit losses | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 10,515 |  |
Balance at the end of the period |  |  | 10,515 |
Reserve for unfunded lending commitments |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 135 | 122 | 124
Provision for credit losses |  | 23 | 13 | (2)
Balance at the end of the period |  | 195 | 135 | 122
Reserve for unfunded lending commitments | Other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  |  | 0 | 0
Provision for credit losses |  |  |  | 0
Balance at the end of the period |  |  |  | 0
Reserve for unfunded lending commitments | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 37 |  |
Balance at the end of the period |  |  | 37 |
Reserve for unfunded lending commitments | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 172 |  |
Balance at the end of the period |  |  | 172 |
Combined allowance and reserve |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 7,343 | 7,342 |
Balance at the end of the period |  | 15,759 | 7,343 | 7,342
Combined allowance and reserve | Other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  |  | 0 |
Balance at the end of the period |  |  |  | 0
Credit Card | Allowance for credit losses |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 5,395 | 5,535 | 5,648
Charge-offs |  | (5,749) | (6,711) | (6,657)
Recoveries |  | 1,479 | 1,562 | 1,588
Net charge-offs |  | (4,270) | (5,149) | (5,069)
Provision for credit losses |  | 7,327 | 4,992 | 4,984
Allowance build (release) for credit losses |  | 3,057 | (157) | (85)
Other changes |  | 36 | 17 | (28)
Balance at the end of the period |  | 11,191 | 5,395 | 5,535
Credit Card | Allowance for credit losses | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 2,241 |  |
Balance at the end of the period |  |  | 2,241 |
Credit Card | Allowance for credit losses | Finance charge and fee reserve reclassification |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 462 |  |
Balance at the end of the period |  |  | 462 |
Credit Card | Allowance for credit losses | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 8,098 |  |
Balance at the end of the period |  |  | 8,098 |
Credit Card | Reserve for unfunded lending commitments |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 | 0 | 0
Provision for credit losses |  | 0 | 0 | 0
Balance at the end of the period |  | 0 | 0 | 0
Credit Card | Reserve for unfunded lending commitments | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 |  |
Balance at the end of the period |  |  | 0 |
Credit Card | Reserve for unfunded lending commitments | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 |  |
Balance at the end of the period |  |  | 0 |
Credit Card | Combined allowance and reserve |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 5,395 | 5,535 |
Balance at the end of the period |  | 11,191 | 5,395 | 5,535
Consumer Banking | Allowance for credit losses |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 1,038 | 1,048 | 1,242
Charge-offs |  | (1,534) | (1,917) | (1,832)
Recoveries |  | 956 | 970 | 851
Net charge-offs |  | (578) | (947) | (981)
Provision for credit losses |  | 1,753 | 937 | 841
Allowance build (release) for credit losses |  | 1,175 | (10) | (140)
Other changes |  | 0 | 0 | (54)
Balance at the end of the period |  | 2,715 | 1,038 | 1,048
Consumer Banking | Allowance for credit losses | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 502 |  |
Balance at the end of the period |  |  | 502 |
Consumer Banking | Allowance for credit losses | Finance charge and fee reserve reclassification |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 |  |
Balance at the end of the period |  |  | 0 |
Consumer Banking | Allowance for credit losses | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 1,540 |  |
Balance at the end of the period |  |  | 1,540 |
Consumer Banking | Reserve for unfunded lending commitments |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 5 | 4 | 7
Provision for credit losses |  | 0 | 1 | (3)
Balance at the end of the period |  | 0 | 5 | 4
Consumer Banking | Reserve for unfunded lending commitments | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | (5) |  |
Balance at the end of the period |  |  | (5) |
Consumer Banking | Reserve for unfunded lending commitments | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 |  |
Balance at the end of the period |  |  | 0 |
Consumer Banking | Combined allowance and reserve |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 1,043 | 1,052 |
Balance at the end of the period |  | 2,715 | 1,043 | 1,052
Commercial Banking | Allowance for credit losses |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 775 | 637 | 611
Charge-offs |  | (394) | (181) | (119)
Recoveries |  | 17 | 25 | 63
Net charge-offs |  | (377) | (156) | (56)
Provision for credit losses |  | 1,158 | 294 | 82
Allowance build (release) for credit losses |  | 781 | 138 | 26
Other changes |  | 0 | 0 | 0
Balance at the end of the period |  | 1,658 | 775 | 637
Commercial Banking | Allowance for credit losses | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 102 |  |
Balance at the end of the period |  |  | 102 |
Commercial Banking | Allowance for credit losses | Finance charge and fee reserve reclassification |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 0 |  |
Balance at the end of the period |  |  | 0 |
Commercial Banking | Allowance for credit losses | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 877 |  |
Balance at the end of the period |  |  | 877 |
Commercial Banking | Reserve for unfunded lending commitments |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 130 | 118 | 117
Provision for credit losses |  | 23 | 12 | 1
Balance at the end of the period |  | 195 | 130 | 118
Commercial Banking | Reserve for unfunded lending commitments | Cumulative effects from adoption of new accounting standards |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 42 |  |
Balance at the end of the period |  |  | 42 |
Commercial Banking | Reserve for unfunded lending commitments | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 172 |  |
Balance at the end of the period |  |  | 172 |
Commercial Banking | Combined allowance and reserve |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Balance at the beginning of the period |  | 905 | 755 |
Balance at the end of the period |  | $ 1,853 | $ 905 | 755
Partnership Credit Card Loan Portfolio | Allowance for credit losses |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Allowance build (release) for credit losses | $ 327 |  |  |
Residential Portfolio Segment | Other |  |  |  |
Allowance for Credit Losses [Roll Forward] |  |  |  |
Gain in other category |  |  |  | 499
Benefit for credit losses |  |  |  | $ 46

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- Definition Financing Receivable, Allowance For Credit Loss, Adjustments, Other + References No definition available. + Details
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- Definition Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448 + Details
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- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(2)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121599878&loc=SL82895884-210446 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 + Details
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- Definition Amount of increase (decrease) in allowance for credit loss on financing receivable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 + Details
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- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 + Details
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- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448 + Details
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- Definition The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121581245&loc=d3e21310-158488 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121581245&loc=d3e21286-158488 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=117337389&loc=d3e21493-158490 + Details
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