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Employee Benefits - Schedule of Fair Value of Other Plan Assets (Details) - Pension Plan - Other - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | $ 1,430 | $ 1,497 | $ 1,303
Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 451 | 507 |
Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Cash and cash equivalents |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 29 | 37 |
Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 29 | 37 |
Cash and cash equivalents | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Cash and cash equivalents | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Equity securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 72 | 75 |
Equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 72 | 75 |
Equity securities | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Equity securities | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Equity investments, Pooled funds |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 316 | 290 |
Equity investments, Pooled funds | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Equity investments, Pooled funds | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Equity investments, Pooled funds | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Government and agency bonds |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 350 | 395 |
Government and agency bonds | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 350 | 395 |
Government and agency bonds | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Government and agency bonds | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Fixed Income Investments, Pooled Funds |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 597 | 627 |
Fixed Income Investments, Pooled Funds | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Fixed Income Investments, Pooled Funds | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Fixed Income Investments, Pooled Funds | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Alternative investments |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 55 | 63 |
Alternative investments | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Alternative investments | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Alternative investments | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Real estate |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 11 | 10 |
Real estate | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Real estate | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | 0 | 0 |
Real estate | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined benefit plan, plan assets | $ 0 | $ 0 |

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