KW UNSECURED DEBT - 2024 Notes (Details) - Senior Notes - 5.875% Senior Notes Due 2024 - USD ($)	Dec. 31, 2021	Jan. 27, 2021
Debt Instrument [Line Items]
Debt face value	$ 1,200,000,000
Interest rate (as a percent)	5.875%
Repurchased face amount		$ 1,000,000,000

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant