Investments - Other Segments and Holding Company (Details) - USD ($) $ in Millions	15 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Schedule of Investments
Investments	$ 3,315	$ 3,012
Other Segments and Holding Company
Schedule of Investments
Investments	112	114
Portion of unrealized (losses) gains that relates to equity securities still held	0
Equity method investments | Other Segments and Holding Company
Schedule of Investments
Investments	98	100
Held-to-maturity Securities [Member] | Other Segments and Holding Company
Schedule of Investments
Investments	11	11
Other investments measured at fair value | Other Segments and Holding Company
Schedule of Investments
Investments	$ 3	$ 3