Schedule II - Condensed Financial Information of Registrant - Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities:
Net Cash Provided by (Used in) Operating Activities	$ 6,673	$ 5,749	$ 3,816
Investing Activities:
Net (purchases) sales of short-term investments	(269)	(696)	467
Acquisitions, net of cash	852	0	0
Other	(30)	(23)	125
Net Cash Used For Investing Activities	(4,461)	(5,468)	(3,101)
Financing Activities:
Purchases of common shares under share repurchase program	(24)	0	(586)
Proceeds from common shares issued, net	7	(2)	6
Common dividends paid	(1,866)	0	0
Preferred dividends paid	(40)	(40)	(40)
Net Cash Used For Financing Activities	(1,925)	(69)	(706)
Increase (decrease) in cash and restricted cash	262	225	(41)
Cash and restricted cash, beginning of year	1,498	1,273	1,314
Cash and restricted cash, end of year	1,760	1,498	1,273
Parent
Operating Activities:
Net Cash Provided by (Used in) Operating Activities	2,398	46	621
Investing Activities:
Net (purchases) sales of short-term investments	(26)	(8)	(5)
Acquisitions, net of cash	(450)	0	0
Other	5	1	(1)
Net Cash Used For Investing Activities	(471)	(7)	(6)
Financing Activities:
Purchases of common shares under share repurchase program	(24)	0	(586)
Proceeds from common shares issued, net	7	(2)	6
Common dividends paid	(1,866)	0	0
Preferred dividends paid	(40)	(40)	(40)
Net Cash Used For Financing Activities	(1,923)	(42)	(620)
Increase (decrease) in cash and restricted cash	4	(3)	(5)
Cash and restricted cash, beginning of year	9	12	17
Cash and restricted cash, end of year	$ 13	$ 9	$ 12