Goodwill and Other Intangibles - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill, impairment loss		$ (26)
Amortizable intangible assets related to acquisitions	$ 213		$ 213	$ 108
Accumulated amortization	39		39	24
Amortization of intangible assets			$ 15	$ 11	$ 6
Weighted average useful life of finite-lived intangible assets acquired			6 years
Future amortization of intangibles in next year	20		$ 20
Future amortization of intangibles in year two	19		19
Future amortization of intangibles in year three	19		19
Future amortization of intangibles in year four	20		20
Future amortization of intangibles in year five	17		17
Future amortization of intangibles after year five	118		$ 118
Verikai, Inc.
Goodwill [Line Items]
Goodwill, impairment loss	$ (26)