Segments of Operations - Earnings before income taxes by segment and sub-segment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	$ 1,239	$ 1,221	$ 391
Realized gains (losses) on securities	(116)	110	(75)
Realized gains on subsidiaries	0	4	23
Earnings from continuing operations before income taxes	1,123	1,335	339
Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	776	733	224
Investment and other income, net	643	657	360
Earnings before realized gains (losses) and income taxes	1,419	1,390	584
Other
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	(180)	(220)	(215)
Other \| Real estate-related investments \| Continuing operations
Segment Reporting Information [Line Items]
Earnings from real-estate related investments, net of DAC	0	51	22
Property and transportation \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	208	279	181
Specialty casualty \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	500	377	223
Specialty financial \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	114	96	50
Other specialty \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	(42)	(15)	(28)
Other lines \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	$ (4)	$ (4)	$ (202)

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Net investment income plus other income less other expenses.

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Underwriting income (loss) for the property and casualty insurance segment, which is calculated as premiums earned less losses and loss adjustment expenses less commissions and other underwriting expenses.

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Amount of gain (loss) on sale or disposal of equity in securities of subsidiaries.

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