Disposition of Metropolitan Property and Casualty Insurance Company - Narrative (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net investment gains (losses)									$ (2,824)	$ (1,260)	$ 1,543
Net income (loss)	$ 614	$ 495	$ 408	$ 85	$ 1,581	$ 1,167	$ 915	$ 1,639	1,602	5,302	6,876
Income (loss) from continuing operations before provision for income tax									$ 2,162	$ 6,364	8,518
Metropolitan Property and Casualty Insurance Company
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses											3,900	$ 3,900
Net investment gains (losses)											1,400
Net income (loss)											1,000
Income (loss) from continuing operations before provision for income tax											$ 121