Investments - Schedule of sources of net investment income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net Investment Income [Line Items]
Investment income	$ 203	$ 173	$ 425	$ 407
Equity in earnings of partnerships and similar investments	28	76	85	209
Investment expenses	(5)	(5)	(10)	(9)
Net investment income	198	168	415	398
Fixed maturities: \| Net investment income
Net Investment Income [Line Items]
Investment income	124	85	243	165
Fixed maturities: \| Net investment income
Net Investment Income [Line Items]
Investment income	7	0	10	0
Equity securities \| Net investment income
Net Investment Income [Line Items]
Change in fair value of equity securities	13	(9)	29	(2)
Other
Net Investment Income [Line Items]
Investment income	22	13	40	20
Net investment income \| Equity securities
Net Investment Income [Line Items]
Investment income	$ 9	$ 8	$ 18	$ 15

Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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