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Business Combinations - Schedule of Business Acquisition, Pro Forma Information (Details) - CIT Group Inc. - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Business Acquisition [Line Items] |  |  |  |
Business acquisition, pro forma net income (loss) | $ 338 | $ 340 | $ 955 | $ 1,112
Interest income |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Business acquisition, pro forma revenue | 906 | 714 | 2,373 | 2,152
Noninterest income |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Business acquisition, pro forma revenue | $ 433 | $ 515 | $ 1,276 | $ 2,014

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