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Investment Securities - Securities in Gross Unrealized Loss Position (Details) $ in Millions | Sep. 30, 2022 USD ($) security | Dec. 31, 2021 USD ($) security
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 40,121 | $ 41,701
Fair Value - 12 Months or Longer | 32,496 | 9,410
Fair Value - Total | 72,617 | 51,111
Gross Unrealized Loss - Less than 12 Months | (3,821) | (670)
Gross Unrealized Loss - 12 Months or Longer | (7,118) | (326)
Gross Unrealized Loss - Total | $ (10,939) | $ (996)
Number of securities in gross unrealized loss positions | security | 2,730 | 740
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 4,593 |
Fair Value - 12 Months or Longer | 0 |
Fair Value - Total | 4,593 |
Gross Unrealized Loss - Less than 12 Months | (98) |
Gross Unrealized Loss - 12 Months or Longer | 0 |
Gross Unrealized Loss - Total | (98) |
RMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 30,124 | $ 37,492
Fair Value - 12 Months or Longer | 30,154 | 8,606
Fair Value - Total | 60,278 | 46,098
Gross Unrealized Loss - Less than 12 Months | (3,285) | (632)
Gross Unrealized Loss - 12 Months or Longer | (6,784) | (299)
Gross Unrealized Loss - Total | (10,069) | (931)
RMBS, Non-agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 16 | 3
Fair Value - 12 Months or Longer | 3 | 1
Fair Value - Total | 19 | 4
Gross Unrealized Loss - Less than 12 Months | (1) | 0
Gross Unrealized Loss - 12 Months or Longer | 0 | 0
Gross Unrealized Loss - Total | (1) | 0
RMBS |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 30,140 | 37,495
Fair Value - 12 Months or Longer | 30,157 | 8,607
Fair Value - Total | 60,297 | 46,102
Gross Unrealized Loss - Less than 12 Months | (3,286) | (632)
Gross Unrealized Loss - 12 Months or Longer | (6,784) | (299)
Gross Unrealized Loss - Total | (10,070) | (931)
CMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 4,866 | 2,999
Fair Value - 12 Months or Longer | 2,258 | 803
Fair Value - Total | 7,124 | 3,802
Gross Unrealized Loss - Less than 12 Months | (430) | (36)
Gross Unrealized Loss - 12 Months or Longer | (331) | (27)
Gross Unrealized Loss - Total | (761) | (63)
Other securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 522 | 1,207
Fair Value - 12 Months or Longer | 81 | 0
Fair Value - Total | 603 | 1,207
Gross Unrealized Loss - Less than 12 Months | (7) | (2)
Gross Unrealized Loss - 12 Months or Longer | (3) | 0
Gross Unrealized Loss - Total | $ (10) | $ (2)

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