Guarantor and Non-Guarantor Financial Statements (Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income	$ 49.9	$ (2.6)
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	(1.2)	(14.4)
Amounts reclassified out of AOCI during the period	1.2	0
Unrealized forward contract, foreign currency (loss) gain	(1.5)	3.6
Total other comprehensive loss for the period	(1.5)	(10.8)
Comprehensive income (loss)	48.4	(13.4)
Comprehensive (income) loss attributable to noncontrolling interests	(37.4)	1.0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	11.0	(12.4)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	49.9	(2.6)
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	(1.2)	(14.4)
Amounts reclassified out of AOCI during the period	1.2
Unrealized forward contract, foreign currency (loss) gain	(1.5)	3.6
Total other comprehensive loss for the period	(1.5)	(10.8)
Comprehensive income (loss)	48.4	(13.4)
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	48.4	(13.4)
Kennedy-Wilson, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	51.7	(0.9)
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	(1.2)	(14.4)
Amounts reclassified out of AOCI during the period	1.2
Unrealized forward contract, foreign currency (loss) gain	(1.5)	3.6
Total other comprehensive loss for the period	(1.5)	(10.8)
Comprehensive income (loss)	50.2	(11.7)
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	50.2	(11.7)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	81.5	14.6
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	(5.1)	(12.9)
Amounts reclassified out of AOCI during the period	0
Unrealized forward contract, foreign currency (loss) gain	2.4	3.2
Total other comprehensive loss for the period	(2.7)	(9.7)
Comprehensive income (loss)	78.8	4.9
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	78.8	4.9
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	77.3	8.7
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	(0.9)	(2.0)
Amounts reclassified out of AOCI during the period	1.2
Unrealized forward contract, foreign currency (loss) gain	0	0
Total other comprehensive loss for the period	0.3	(2.0)
Comprehensive income (loss)	77.6	6.7
Comprehensive (income) loss attributable to noncontrolling interests	(37.4)	1.0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	40.2	7.7
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	(210.5)	(22.4)
Other comprehensive income (loss), net of tax:
Unrealized foreign currency translation loss	7.2	29.3
Amounts reclassified out of AOCI during the period	(2.4)
Unrealized forward contract, foreign currency (loss) gain	(0.9)	(6.8)
Total other comprehensive loss for the period	3.9	22.5
Comprehensive income (loss)	(206.6)	0.1
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Kennedy-Wilson Holdings, Inc.	$ (206.6)	$ 0.1