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Share-based Compensation and Employee Benefits - Fair Value of Pension and OPEB Assets by Level of Assets (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | --- | ---
Pension Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | $ 1,614 | $ 1,562 | $ 1,741
Pension Benefits | Total |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 583 | 585 |
Pension Benefits | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 203 | 143 |
Pension Benefits | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 380 | 442 |
Pension Benefits | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 1,031 | 977 |
Pension Benefits | Short-term Investment Funds | Total |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 32 |
Pension Benefits | Short-term Investment Funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 0 |
Pension Benefits | Short-term Investment Funds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 32 |
Pension Benefits | Short-term Investment Funds | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 29 | 0 |
Pension Benefits | Equities | Total |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 203 | 143 |
Pension Benefits | Equities | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 203 | 143 |
Pension Benefits | Equities | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 0 |
Pension Benefits | Fixed Income Securities | Total |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 380 | 410 |
Pension Benefits | Fixed Income Securities | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 0 |
Pension Benefits | Fixed Income Securities | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 380 | 410 |
Pension Benefits | Common/Collective Trusts | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | $ 1,002 | $ 976 |
Pension Benefits | Common/Collective Trusts Invested in Equity Securities | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of category allocated to investments | 66.00% | 64.00% |
Pension Benefits | Common/Collective Trusts Invested in Fixed Income Securities | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of category allocated to investments | 22.00% | 23.00% |
Pension Benefits | Common/Collective Trusts Invested in Real Estate | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of category allocated to investments | 12.00% | 13.00% |
Pension Benefits | Private Limited Partnerships | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | $ 0 | $ 1 |
OPEB |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 331 | 323 | $ 302
OPEB | Short-term Investment Funds | Total |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 3 | 5 |
OPEB | Short-term Investment Funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 0 | 0 |
OPEB | Short-term Investment Funds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | 3 | 5 |
OPEB | Common/Collective Trusts | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total plan assets fair value | $ 328 | $ 318 |
OPEB | Common/Collective Trusts Invested in Equity Securities | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of category allocated to investments | 62.00% | 62.00% |
OPEB | Common/Collective Trusts Invested in Fixed Income Securities | Measured at NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of category allocated to investments | 38.00% | 38.00% |
Class P | Pension Benefits | Equities | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Amount of KMI securities invested in | $ 167 | $ 107 |

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