Goodwill and Other Intangibles - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the goodwill			$ 0
Goodwill	$ 305,000,000		305,000,000		$ 305,000,000
Amortizable intangible assets related to property and casualty insurance acquisitions	199,000,000		199,000,000		213,000,000
Accumulated amortization	53,000,000		53,000,000		$ 39,000,000
Amortization of intangible assets	$ 5,000,000	$ 5,000,000	$ 14,000,000	$ 11,000,000