UNCONSOLIDATED INVESTMENTS -Summarized Financial Data (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents		$ 439.3	$ 524.8	$ 439.3	$ 524.8
Accounts receivable		40.8	36.1	40.8	36.1
Real estate and acquired in place lease values, net of accumulated depreciation and amortization, net		5,188.1	5,059.8	5,188.1	5,059.8
Other assets		216.1	177.9	216.1	177.9
Total assets	[1]	8,271.8	7,876.5	8,271.8	7,876.5
Liabilities
Total liabilities	[1]	6,261.4	6,072.6	6,261.4	6,072.6
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity		1,964.0	1,777.6	1,964.0	1,777.6
Noncontrolling interests		46.4	26.3	46.4	26.3
Total equity		2,010.4	1,803.9	2,010.4	1,803.9	$ 1,672.7	$ 1,719.2
Total liabilities and equity		8,271.8	7,876.5	8,271.8	7,876.5
Interest expense				(220.8)	(192.4)	(201.9)
Other income (loss)				36.1	(5.0)	(2.3)
Net income				101.9	336.4	107.8
Income attributable to partner				8.2	6.0	(2.3)
Income from unconsolidated investments		178.4	389.0	178.4	389.0	81.0
VHH
Equity
Unrealized fair value gains				270.7	77.4	31.3
Interest expense				(45.6)	(37.5)	(31.8)
Other income (loss)				0.0	(0.1)	(0.9)
Income attributable to partner				(195.3)	(78.3)	(46.5)
Income from unconsolidated investments				119.8	41.4	22.8
MF Seed Portfolio
Equity
Unrealized fair value gains				56.1	140.6
Interest expense				(17.6)	(8.2)
Other income (loss)				(4.1)	(11.8)
Income attributable to partner				(33.0)	(54.8)
Income from unconsolidated investments				45.1	88.9
Rental | VHH
Equity
Total revenue				131.0	114.7	102.1
Rental expenses				(41.0)	(34.8)	(31.4)
Rental | MF Seed Portfolio
Equity
Total revenue				64.8	31.6
Rental expenses				(21.1)	(8.5)
MF Seed Portfolio
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents		12.4	10.9	12.4	10.9
Accounts receivable		2.0	2.4	2.0	2.4
Real estate and acquired in place lease values, net of accumulated depreciation and amortization, net		970.5	943.5	970.5	943.5
Other assets		1.1	1.5	1.1	1.5
Total assets		986.0	958.3	986.0	958.3
Liabilities
Accounts payable and accrued expenses		5.4	5.2	5.4	5.2
Mortgage debt		448.7	457.0	448.7	457.0
Total liabilities		454.1	462.2	454.1	462.2
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity		291.9	268.6	291.9	268.6
Noncontrolling interests		240.0	227.5	240.0	227.5
Total equity		531.9	496.1	531.9	496.1
Total liabilities and equity		986.0	958.3	986.0	958.3
Net income				78.1	143.7
VHH
Schedule of Equity Method Investments [Line Items]
Cash and cash equivalents		37.0	31.9	37.0	31.9
Accounts receivable		4.4	4.9	4.4	4.9
Real estate and acquired in place lease values, net of accumulated depreciation and amortization, net		1,802.7	1,553.3	1,802.7	1,553.3
Other assets		2.0	0.0	2.0	0.0
Total assets		1,846.1	1,590.1	1,846.1	1,590.1
Liabilities
Accounts payable and accrued expenses		17.6	19.9	17.6	19.9
Mortgage debt		1,180.6	1,188.6	1,180.6	1,188.6
Total liabilities		1,198.2	1,208.5	1,198.2	1,208.5
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity		271.8	157.9	271.8	157.9
Noncontrolling interests		376.1	223.7	376.1	223.7
Total equity		647.9	381.6	647.9	381.6
Total liabilities and equity		$ 1,846.1	$ 1,590.1	1,846.1	1,590.1
Net income				$ 315.1	$ 119.7	$ 69.3

[1] The assets and liabilities as of December 31, 2022 include $169.8 million (including cash held by consolidated investments of $6.1 million and real estate and acquired in place lease values, net of accumulated depreciation and amortization of $137.8 million) and $82.4 million (including investment debt of $51.2 million), respectively, from consolidated variable interest entities ("VIEs"). The assets and liabilities as of December 31, 2021 include $189.6 million (including cash held by consolidated investments of $11.5 million and real estate and acquired in place lease values, net of accumulated depreciation and amortization of $152.8 million) and $129.2 million (including investment debt of $103.3 million), respectively, from VIEs. These assets can only be used to settle obligations of the consolidated VIEs, and the liabilities do not have recourse to the Company.