Claims, Lawsuits, and Other Contingencies - Legal Narrative (Details) - Pending Litigation £ in Millions, $ in Millions		1 Months Ended
	Sep. 30, 2023 USD ($)	Apr. 30, 2021 GBP (£) plaintiff	Aug. 31, 2020 USD ($) plaintiff	Nov. 30, 2019 USD ($) defendant	Nov. 30, 2018 USD ($)	Apr. 27, 2018 USD ($) fund
Aon Hewitt Investment Consulting Inc
Legal, Guarantees and Indemnifications
Investment losses suffered by plaintiff						$ 200
Investment losses suffered by plaintiff, number of funds | fund						8
Fatal Plain Crash In November 2016
Legal, Guarantees and Indemnifications
Damages sought	$ 35	£ 29	$ 844		$ 16
Number of defendants | defendant				3
Damages sought option 1				$ 300
Damages sought option 2				50
Damages sought option 3				$ 25
Number of plaintiffs | plaintiff		16	43