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Investment Securities - Securities in Gross Unrealized Loss Position (Details) $ in Millions | Dec. 31, 2021 USD ($) security | Dec. 31, 2020 USD ($) security
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 41,701 | $ 9,095
Fair Value - 12 Months or Longer | 9,410 | 2,059
Fair Value - Total | 51,111 | 11,154
Gross Unrealized Loss - Less than 12 Months | (670) | (64)
Gross Unrealized Loss - 12 Months or Longer | (326) | (55)
Gross Unrealized Loss - Total | $ (996) | $ (119)
Number of securities in gross unrealized loss positions | security | 740 | 320
RMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 37,492 | $ 7,424
Fair Value - 12 Months or Longer | 8,606 | 1,791
Fair Value - Total | 46,098 | 9,215
Gross Unrealized Loss - Less than 12 Months | (632) | (57)
Gross Unrealized Loss - 12 Months or Longer | (299) | (51)
Gross Unrealized Loss - Total | (931) | (108)
RMBS, Non-agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 3 | 12
Fair Value - 12 Months or Longer | 1 | 0
Fair Value - Total | 4 | 12
Gross Unrealized Loss - Less than 12 Months | 0 | 0
Gross Unrealized Loss - 12 Months or Longer | 0 | 0
Gross Unrealized Loss - Total | 0 | 0
RMBS |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 37,495 | 7,436
Fair Value - 12 Months or Longer | 8,607 | 1,791
Fair Value - Total | 46,102 | 9,227
Gross Unrealized Loss - Less than 12 Months | (632) | (57)
Gross Unrealized Loss - 12 Months or Longer | (299) | (51)
Gross Unrealized Loss - Total | (931) | (108)
CMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 2,999 | 1,545
Fair Value - 12 Months or Longer | 803 | 267
Fair Value - Total | 3,802 | 1,812
Gross Unrealized Loss - Less than 12 Months | (36) | (7)
Gross Unrealized Loss - 12 Months or Longer | (27) | (4)
Gross Unrealized Loss - Total | (63) | (11)
Other securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 1,207 | 114
Fair Value - 12 Months or Longer | 0 | 1
Fair Value - Total | 1,207 | 115
Gross Unrealized Loss - Less than 12 Months | (2) | 0
Gross Unrealized Loss - 12 Months or Longer | 0 | 0
Gross Unrealized Loss - Total | $ (2) | $ 0

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456 + Details
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 + Details
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