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Business and Basis of Presentation - Gain on Equity Method Investment (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
	Jul. 01, 2023	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule of Equity Method Investments [Line Items]
Equity method investments, fair value	$ 444
Gain on sale of asset management subsidiaries	255	$ 0		$ 255	$ 0	$ 255
Sound Point Agreement
Schedule of Equity Method Investments [Line Items]
Goodwill and intangible assets	155
Sound Point Capital Management, LP
Schedule of Equity Method Investments [Line Items]
Equity method investments, fair value	419
Equity method investments		$ 417	$ 429		$ 417
Gain (loss) on sale of asset management subsidiaries	248		$ (7)
Other consideration
Schedule of Equity Method Investments [Line Items]
Equity method investments, fair value	25
Managed by AssuredIM
Schedule of Equity Method Investments [Line Items]
Equity method investments	189
Assured Healthcare Partners LLC
Schedule of Equity Method Investments [Line Items]
Gain (loss) on sale of asset management subsidiaries	$ 7