GUARANTOR AND NON-GUARANTOR FINANCIAL STATEMENTS - Consolidating Statement of Income (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
Revenue
Total revenue			$ 540.0	$ 453.6	$ 454.0
Expenses
General and administrative			37.2	33.3	34.6
Depreciation and amortization			172.9	166.3	179.6
Total expenses			526.8	549.6	508.1
Income from unconsolidated investments	$ 178.4	$ 389.0	178.4	389.0	81.0
Income from consolidated subsidiaries			0.0	0.0	0.0
Non-operating income (expense)
Gain on sale of real estate, net			103.7	412.7	338.0
Interest expense			(220.8)	(192.4)	(201.9)
Gain (loss) on early extinguishment of debt			27.5	(45.7)	(9.3)
Other income (loss)			36.1	(5.0)	(2.3)
Income before provision for income taxes			138.1	462.6	151.4
Provision for income taxes			(36.2)	(126.2)	(43.6)
Net income			101.9	336.4	107.8
Net income attributable to the noncontrolling interests			(8.2)	(6.0)	2.3
Preferred dividends			(28.9)	(17.2)	(17.2)
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			64.8	313.2	92.9
Reportable Legal Entities | Parent
Revenue
Total revenue			0.0	0.0	0.0
Expenses
Total expenses			29.0	31.8	33.5
Income from unconsolidated investments			0.0	0.0	0.0
Income from consolidated subsidiaries			130.8	368.2	141.3
Non-operating income (expense)
Gain on sale of real estate, net			0.0	0.0	0.0
Interest expense			0.0	0.0	0.0
Gain (loss) on early extinguishment of debt			0.0	0.0	0.0
Other income (loss)			0.1	0.0
Income before provision for income taxes			101.9	336.4	107.8
Provision for income taxes			0.0	0.0	0.0
Net income			101.9	336.4	107.8
Net income attributable to the noncontrolling interests			0.0	0.0	0.0
Preferred dividends			(28.9)	(17.2)	(17.2)
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			73.0	319.2	90.6
Reportable Legal Entities | Kennedy-Wilson, Inc.
Revenue
Total revenue			0.2	0.3	0.0
Expenses
Total expenses			92.7	108.1	86.7
Income from unconsolidated investments			1.1	3.2	0.6
Income from consolidated subsidiaries			314.4	676.8	320.1
Non-operating income (expense)
Gain on sale of real estate, net			0.0	(1.7)	0.0
Interest expense			(92.6)	(73.3)	(69.5)
Gain (loss) on early extinguishment of debt			0.0	(26.5)	0.0
Other income (loss)			15.6	0.7	2.0
Income before provision for income taxes			146.0	471.4	166.5
Provision for income taxes			(15.2)	(103.2)	(25.2)
Net income			130.8	368.2	141.3
Net income attributable to the noncontrolling interests			0.0	0.0	0.0
Preferred dividends			0.0	0.0	0.0
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			130.8	368.2	141.3
Reportable Legal Entities | Guarantor Subsidiaries
Revenue
Total revenue			225.1	208.8	218.6
Expenses
Total expenses			172.5	214.8	201.0
Income from unconsolidated investments			12.0	99.0	(0.6)
Income from consolidated subsidiaries			230.7	508.7	294.0
Non-operating income (expense)
Gain on sale of real estate, net			68.1	129.6	65.9
Interest expense			(41.8)	(43.3)	(48.6)
Gain (loss) on early extinguishment of debt			(1.6)	(0.6)	(3.7)
Other income (loss)			(1.3)	(1.2)	(3.8)
Income before provision for income taxes			318.7	686.2	320.8
Provision for income taxes			(4.3)	(9.4)	(0.7)
Net income			314.4	676.8	320.1
Net income attributable to the noncontrolling interests			0.0	0.0	0.0
Preferred dividends			0.0	0.0	0.0
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			314.4	676.8	320.1
Reportable Legal Entities | Non-guarantor Subsidiaries
Revenue
Total revenue			314.7	244.5	235.4
Expenses
Total expenses			232.6	194.9	186.9
Income from unconsolidated investments			165.3	286.8	81.0
Income from consolidated subsidiaries			0.0	0.0	0.0
Non-operating income (expense)
Gain on sale of real estate, net			35.6	284.8	272.1
Interest expense			(86.4)	(75.8)	(83.8)
Gain (loss) on early extinguishment of debt			29.1	(18.6)	(5.6)
Other income (loss)			21.7	(4.5)	(0.5)
Income before provision for income taxes			247.4	522.3	311.7
Provision for income taxes			(16.7)	(13.6)	(17.7)
Net income			230.7	508.7	294.0
Net income attributable to the noncontrolling interests			(8.2)	(6.0)	2.3
Preferred dividends			0.0	0.0	0.0
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			222.5	502.7	296.3
Elimination
Revenue
Total revenue			0.0	0.0	0.0
Expenses
Total expenses			0.0	0.0	0.0
Income from unconsolidated investments			0.0	0.0	0.0
Income from consolidated subsidiaries			(675.9)	(1,553.7)	(755.4)
Non-operating income (expense)
Gain on sale of real estate, net			0.0	0.0	0.0
Interest expense			0.0
Gain (loss) on early extinguishment of debt			0.0	0.0	0.0
Other income (loss)			0.0		0.0
Income before provision for income taxes			(675.9)	(1,553.7)	(755.4)
Provision for income taxes			0.0	0.0	0.0
Net income			(675.9)	(1,553.7)	(755.4)
Net income attributable to the noncontrolling interests			0.0	0.0	0.0
Preferred dividends			0.0	0.0	0.0
Net income attributable to Kennedy-Wilson Holdings, Inc. common shareholders			$ (675.9)	$ (1,553.7)	$ (755.4)