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.