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General (Effects of Adoption of ASU 2018-12, Stockholders' Equity) (Details) - USD ($) $ in Millions | Mar. 31, 2023 | Dec. 31, 2022 | Mar. 31, 2022 | [2] | Dec. 31, 2021 | [2] | Dec. 31, 2020
--- | --- | --- | --- | --- | --- | --- | ---
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity | $ 8,667 | $ 8,548 | [1] | $ 9,698 |  |
Accumulated Other Comprehensive (Loss) Income |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity | (3,308) | (3,598) |  | (2,380) | $ (1,360) | $ (1,537)
Retained Earnings |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity | $ 9,191 | 9,336 |  | $ 9,277 | 9,639 | 9,075
Prior to Adoption |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  | 8,825 |  |  |  |
Prior to Adoption | Accumulated Other Comprehensive (Loss) Income |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  | (3,557) |  |  | 320 | 803
Prior to Adoption | Retained Earnings |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  | $ 9,572 |  |  | $ 9,663 | 9,081
De-recognition of shadow reserves | Accumulated Other Comprehensive (Loss) Income |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | 2,601
De-recognition of shadow reserves | Retained Earnings |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | 0
Re-measurement using an upper-medium grade fixed income instrument yield discount rate | Accumulated Other Comprehensive (Loss) Income |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | (4,941)
Re-measurement using an upper-medium grade fixed income instrument yield discount rate | Retained Earnings |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | 0
Other adjustments | Accumulated Other Comprehensive (Loss) Income |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | 0
Other adjustments | Retained Earnings |  |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |  |
Total stockholders' equity |  |  |  |  |  | $ (6)
[1] | As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.
[2] | As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Condensed Consolidated Financial Statements for additional information.

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