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Employee Benefit Plans (Fair Values of the Corporation's Qualified Defined Benefit Pension Plan Investments Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | $ 1,269 | $ 1,569
Fair value of plan assets in qualified defined benefit pension plan | 2,499 | 3,454
Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 534 | 599
Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 676 | 893
Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan | 20 | 27
Debt securities | Collective investments funds |  |
Fair value of plan assets in qualified defined benefit pension plan | 1,230 | 1,885
Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 39 | 50
Level 1 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 531 | 595
Level 1 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 531 | 595
Level 1 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 1 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 1 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 2 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 699 | 924
Level 2 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 3 | 4
Level 2 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 676 | 893
Level 2 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan | 20 | 27
Level 2 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 |  |
Fair value of plan assets in qualified defined benefit pension plan, Excluding assets valued at net asset value | 39 | 50
Level 3 | Debt securities | U.S. Treasury and other U.S. government agency securities |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 | Debt securities | Corporate and municipal bonds and notes |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 | Debt securities | Mortgage-backed secutities |  |
Fair value of plan assets in qualified defined benefit pension plan | 0 | 0
Level 3 | Private placements | Private placements |  |
Fair value of plan assets in qualified defined benefit pension plan | $ 39 | $ 50

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