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Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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Financial Assets & Liabilities - Kyndryl Common Stock (Details) $ / shares in Units, shares in Millions, $ in Millions						3 Months Ended	9 Months Ended
	Aug. 11, 2022 USD ($) shares	Aug. 05, 2022 USD ($)	May 23, 2022 USD ($) $ / shares	May 18, 2022 USD ($)	Nov. 03, 2021	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Financial assets and financial liabilities measured at fair value on a recurring basis:
Proceeds from short term credit		$ 300.0		$ 357.0
Short-term debt						$ 5,937.0	$ 5,937.0	$ 6,787.0
Strike price \| $ / shares			$ 13.95
Debt converted amount	$ 229.0		$ 311.0
Repayment of debt	$ 71.0		$ 46.0
Fair value of the swap						$ 85.0	$ 85.0
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]						Other accrued expenses and liabilities	Other accrued expenses and liabilities
Adjustment for the mark-to-market on the related debt						$ 0.0
Short term debt, fair value						184.0	$ 184.0
Exchangeable debt
Financial assets and financial liabilities measured at fair value on a recurring basis:
Short-term debt						311.0	311.0
Other (income) and expense
Financial assets and financial liabilities measured at fair value on a recurring basis:
Unrealized gain (loss)						3.0	(85.0)
Changes in fair value of the debt						(34.0)	$ (127.0)
Kyndryl Holdings, Inc
Financial assets and financial liabilities measured at fair value on a recurring basis:
Ownership interest by stockholders (in percent)					19.90%
Amount of retained interest transferred			9.95%
Equity on conversion debt	22.3		22.3
Percentage of retained interest in investment transferred							100.00%
Equity on debt conversion derecognized \| shares	22.3
Kyndryl Holdings, Inc \| Other (income) and expense
Financial assets and financial liabilities measured at fair value on a recurring basis:
Unrealized loss							$ 93.0
Realized gain (loss)						11.0	(174.0)
Kyndryl Holdings, Inc \| Prepaid expenses and other current assets
Financial assets and financial liabilities measured at fair value on a recurring basis:
Investment Owned, at Fair Value						$ 184.0	$ 184.0	$ 807.0
Kyndryl Holdings, Inc
Financial assets and financial liabilities measured at fair value on a recurring basis:
Period in which shares are intended to be disposed of after separation					12 months