Investment Information - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) lots	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) lots	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) lots
Continuous unrealized loss, qualitative disclosures:
Number of positions in an unrealized loss position (lots) | lots	11,140		11,140		9,810
Total number of positions (lots) | lots	14,320		14,320		12,590
Largest single loss	$ 6		$ 6		$ 7
Narrative items:
Equity securities, at fair value	894		894		$ 860
Equity in net (loss) income of investment funds accounted for using the equity method	$ 59	$ (19)	$ 176	$ 75
Minimum
Narrative items:
Time lag for reporting			1 month
Maximum
Narrative items:
Time lag for reporting			3 months