Disposition of Metropolitan Property and Casualty Insurance Company - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 3,902	$ 0	$ 0
Net investment gains (losses)	1,529	(110)	444
Gain (Loss) on Sale of Business	6,575	5,418	5,909
Income (loss) from continuing operations before provision for income tax	8,126	6,927	6,795
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
Gain (Loss) on Sale of Business	1,000
Income (loss) from continuing operations before provision for income tax	$ 121	$ 399	$ 291