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Investment Securities - Securities in Gross Unrealized Loss Position (Detail) $ in Millions | Jun. 30, 2020 USD ($) Security | Dec. 31, 2019 USD ($)
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 6,879 | $ 15,882
Fair Value - 12 Months or Longer | 3,941 | 12,252
Fair Value - Total | 10,820 | 28,134
Gross Unrealized Loss - Less than 12 Months | (37) | (120)
Gross Unrealized Loss - 12 Months or Longer | (53) | (212)
Gross Unrealized Loss - Total | $ (90) | (332)
Number of securities in gross unrealized loss positions | Security | 350 |
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | $ 2,812 | 2,647
Fair Value - 12 Months or Longer | 0 | 0
Fair Value - Total | 2,812 | 2,647
Gross Unrealized Loss - Less than 12 Months | (3) | (4)
Gross Unrealized Loss - 12 Months or Longer | 0 | 0
Gross Unrealized Loss - Total | (3) | (4)
RMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 2,732 | 10,494
Fair Value - 12 Months or Longer | 3,210 | 10,567
Fair Value - Total | 5,942 | 21,061
Gross Unrealized Loss - Less than 12 Months | (30) | (92)
Gross Unrealized Loss - 12 Months or Longer | (47) | (192)
Gross Unrealized Loss - Total | (77) | (284)
RMBS, Non-agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 14 | 35
Fair Value - 12 Months or Longer | 2 | 16
Fair Value - Total | 16 | 51
Gross Unrealized Loss - Less than 12 Months | 0 | (1)
Gross Unrealized Loss - 12 Months or Longer | 0 | (1)
Gross Unrealized Loss - Total | 0 | (2)
RMBS |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 2,746 | 10,529
Fair Value - 12 Months or Longer | 3,212 | 10,583
Fair Value - Total | 5,958 | 21,112
Gross Unrealized Loss - Less than 12 Months | (30) | (93)
Gross Unrealized Loss - 12 Months or Longer | (47) | (193)
Gross Unrealized Loss - Total | (77) | (286)
CMBS, Agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 644 | 2,580
Fair Value - 12 Months or Longer | 724 | 1,563
Fair Value - Total | 1,368 | 4,143
Gross Unrealized Loss - Less than 12 Months | (3) | (23)
Gross Unrealized Loss - 12 Months or Longer | (6) | (19)
Gross Unrealized Loss - Total | (9) | (42)
Other securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value - Less than 12 Months | 677 | 126
Fair Value - 12 Months or Longer | 5 | 106
Fair Value - Total | 682 | 232
Gross Unrealized Loss - Less than 12 Months | (1) | 0
Gross Unrealized Loss - 12 Months or Longer | 0 | 0
Gross Unrealized Loss - Total | $ (1) | $ 0

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