Investments (Details) - Equity Securities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Investment disclosure details
Equity securities, cost	$ 544	$ 553
Gross gains	154	96
Gross losses	11	41
Equity securities, at fair value	687	608
Net recognized gains (losses) on equity securities still held	89	16
Common stock [Member]
Investment disclosure details
Equity securities, cost	500	508
Gross gains	150	93
Gross losses	11	41
Equity securities, at fair value	639	560
Non-redeemable preferred stock [Member]
Investment disclosure details
Equity securities, cost	44	45
Gross gains	4	3
Gross losses	0	0
Equity securities, at fair value	$ 48	$ 48