Basis of Presentation (Details) $ / shares in Units, € in Millions, £ in Millions, $ in Millions										3 Months Ended		6 Months Ended	9 Months Ended
	Nov. 01, 2023 USD ($) shares	Oct. 31, 2023 EUR (€)	Jul. 03, 2023 USD ($)	Jun. 26, 2023 USD ($) shares	Jun. 12, 2023 USD ($) $ / shares shares	May 22, 2023 USD ($) shares	Dec. 14, 2022 USD ($)	Sep. 19, 2022 USD ($) $ / shares shares	Nov. 02, 2021	Sep. 30, 2023 USD ($) country	Sep. 30, 2022 USD ($)	Jun. 30, 2024 GBP (£)	Sep. 30, 2023 USD ($) country shares	Sep. 30, 2022 USD ($)
Basis of Presentation Information
Number of countries in which the entity operates | country										70			70
Total number of warrants repurchased (in shares) | shares				12,200,000
Aggregate purchase price of repurchased shares				$ 200.0
Contributions from noncontrolling interests										$ 8.0	$ 17.0		$ 35.0	$ 22.0
Parent Company
Basis of Presentation Information
Pre-tax loss on deconsolidation							$ 114.0
Total AIG Shareholders' Equity
Basis of Presentation Information
Contributions from noncontrolling interests				(15.0)	$ 71.0			$ 497.0		$ (6.0)			$ (92.0)
AIG
Basis of Presentation Information
Aggregate purchase price of repurchased shares				$ 180.0
IPO And Secondary Offering | Corebridge Financial Inc
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					74,750,000
Secondary Offering | Corebridge Financial Inc
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					9,750,000
Price per share (in USD per share) | $ / shares					$ 16.25
Gross proceeds from sale of stock					$ 1,200.0
IPO | Corebridge Financial Inc
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					65,000,000			80,000,000
Price per share (in USD per share) | $ / shares								$ 21.00
Percentage of stock sold (as a percent)								12.40%
Gross proceeds from sale of stock								$ 1,700.0
Corebridge Financial Inc
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					648,000,000
Ownership (as a percent)										65.60%			65.60%
Corebridge Financial Inc | AIG
Basis of Presentation Information
Total number of warrants repurchased (in shares) | shares													11,000,000
Corebridge Financial Inc | Blackstone
Basis of Presentation Information
Ownership percentage by noncontrolling owners									9.90%
Percent of ownership interest permitted to be sold after first anniversary									25.00%
Percent of ownership interest permitted to be sold after second anniversary									67.00%
Percent of ownership interest permitted to be sold after third anniversary									75.00%
Corebridge Financial Inc | Secondary Offering
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					74,750,000
Corebridge Financial Inc | IPO
Basis of Presentation Information
Shares issued in IPO (in shares) | shares					65,000,000
AIG Life | Assets held-for-sale | Forecast
Basis of Presentation Information
Cash consideration for divestiture of business | £												£ 460
Laya and Other | Assets held-for-sale | Subsequent event
Basis of Presentation Information
Cash consideration for divestiture of business | €		€ 650
Validus Re | Assets held-for-sale
Basis of Presentation Information
Cash consideration for divestiture of business						$ 2,700.0
Share consideration received on transaction (in shares) | shares						1,300,000
Validus Re | Assets held-for-sale | Subsequent event
Basis of Presentation Information
Cash consideration for divestiture of business	$ 2,700.0
Value of share consideration received on transaction	$ 275.0
Share consideration received on transaction (in shares) | shares	1,300,000
Crop Risk Services | Assets held-for-sale
Basis of Presentation Information
Cash consideration for divestiture of business			$ 234.0
Pre-tax gain on disposal of business			$ 126.0