INVESTMENT SECURITIES - Narrative (Details) $ in Millions	9 Months Ended
Sep. 30, 2022 USD ($) position	Dec. 31, 2021 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Book value	$ 15,392	$ 13,440
Debt securities:	$ 13,487	$ 13,497
Maximum individual state general bond obligation as a percentage of total debt securities (percent)	1.00%
Securities in unrealized loss positions, number of positions \| position	1,655
Securities, number of positions \| position	1,905
Dispositions \| Kindred at Home, Hospice and Personal Care Divisions
Financing Receivable, Credit Quality Indicator [Line Items]
Book value	$ 279
Debt securities:	$ 274
S&P AA- rating
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of debt securities considered to be of investment-grade (percent)	95.00%

Debt Securities, Available-for-sale, Securities, Number Of Positions

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Maximum Individual State General Bond Obligation, As Percentage Of Total Debt Securities

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Percentage Of Total Debt Securities, Investment Grade Quality

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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-Section 45
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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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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