Segments of Operations - Earnings before income taxes by segment and sub-segment (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	$ 1,221	$ 391	$ 479
Realized gains (losses) on securities	110	(75)	155
Subsidiaries	4	23	0
Earnings from continuing operations before income taxes	1,335	339	634
Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	733	224	212
Investment and other income, net	657	360	437
Earnings before realized gains (losses) and income taxes	1,390	584	649
Other
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	(220)	(215)	(196)
Other \| Real estate-related investments \| Continuing operations
Segment Reporting Information [Line Items]
Earnings from real-estate related investments, net of DAC	51	22	26
Property and transportation \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	279	181	79
Specialty casualty \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	377	223	175
Specialty financial \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	96	50	92
Other specialty \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	(15)	(28)	(21)
Other lines \| Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	$ (4)	$ (202)	$ (113)

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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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