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v3.21.2

Revenue from Contracts with Clients - Narrative (Details) | 3 Months Ended | 9 Months Ended
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Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Revenue from Contract with Customer [Abstract] |  |  |  |
Total revenues (percentage) | 1.40% | 1.40% | 1.40% | 0.90%
Operating revenues (percentage) | 33.90% | 35.80% | 34.30% | 37.60%

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