Fair Value Measurement - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Assets of consolidated investment vehicles (includes $99 and $331, at fair value)	$ 101	$ 366
Other assets (includes $131 and $123, at fair value)	746	706
Long-term debt	(1,699)	(1,694)
Other liabilities	(498)	(492)
Carrying Amount
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Assets of consolidated investment vehicles (includes $99 and $331, at fair value)	0	19
Other assets (includes $131 and $123, at fair value)	115	79
Financial guaranty insurance contracts	(2,029)	(2,244)
Long-term debt	(1,699)	(1,694)
Other liabilities	(16)	(15)
Estimated Fair Value
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Assets of consolidated investment vehicles (includes $99 and $331, at fair value)	0	19
Other assets (includes $131 and $123, at fair value)	116	80
Financial guaranty insurance contracts	(1,136)	(1,811)
Long-term debt	(1,579)	(1,593)
Other liabilities	$ (16)	$ (15)