Related Parties - Summary of Assets Sub-Advised by Affiliates (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Mortgage loans	$ 12,199	$ 10,631
Investment funds	3,912	3,559
Total assets	$ 138,980	125,505
Apollo affiliates \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Mortgage loans		3,507
Investment funds		157
Trading securities, at fair value		87
Equity securities		2
Funds withheld at interest		4,126
Other investments		70
Total assets		$ 18,746
Percent of assets sub-advised by Apollo affiliates to total AAM-managed assets		18.00%
Apollo affiliates \| Foreign governments \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Available-for-sale securities		$ 153
Apollo affiliates \| Corporate \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Available-for-sale securities		3,398
Apollo affiliates \| CLO \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Available-for-sale securities		5,703
Apollo affiliates \| ABS \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Available-for-sale securities		663
Apollo affiliates \| CMBS \| Related Party \| Sub-allocated assets
Related Party Transaction [Line Items]
Available-for-sale securities		$ 880

Other investments including, but not limited to: partnership interests, credit funds, hedge funds, and private equity.

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Related Party Transaction, Percentage of Assets Managed

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of the reinsurer's funds held on its behalf by the ceding insurer, including funds held in trust, under reinsurance treaties or contracts with the assuming insurer as security for the payment of the obligations thereunder.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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