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Investments (Aggregated Balance Sheet Summarized Financial Information for Partnerships in our Alternative Investment Portfolio) (Details) - Investments Accounted For Under The Equity Method [Member] - USD ($) $ in Millions | Sep. 30, 2019 | Sep. 30, 2018
--- | --- | ---
Investments | $ 43,857 | $ 28,292
Total assets | 45,432 | 30,377
Total liabilities | 5,670 | 4,532
Partners' capital | $ 39,762 | $ 25,845

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